Actinic ray-sensitive or radiation-sensitive resin composition, pattern forming method, method for manufacturing electronic device, and electronic device

ABSTRACT

An actinic ray-sensitive or radiation-sensitive resin composition contains a resin (P) having a partial structure represented by General Formula (X), and a compound capable of generating an acid upon irradiation with actinic ray or radiation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No. PCT/JP2014/080668 filed on Nov. 19, 2014, which claims priority under 35 U.S.C §119(a) to Japanese Patent Application No. 2013-257496 filed on Dec. 12, 2013. Each of the above application(s) is hereby expressly incorporated by reference, in its entirety, into the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, a method for manufacturing an electronic device, and an electronic device. More specifically, the present invention relates to a pattern forming method which is suitable for a process for manufacturing a semiconductor such as an IC, for the manufacture of liquid crystals and a circuit board for a thermal head or the like, and for other lithographic processes of photofabrication; and an actinic ray-sensitive or radiation-sensitive resin composition used in the pattern forming method. In addition, the present invention further relates to a method for manufacturing an electronic device, including the pattern forming method, and an electronic device manufactured by the method.

2. Description of the Related Art

Microfabrication by lithography using a photoresist composition has hitherto been carried out in a process for manufacturing semiconductor devices such as an IC and an LSI.

In recent years, with the progress in increasing integration of an integrated circuit, ultrafine pattern formation is further required, and with regard to this, for example, a resist material using a high-molecular-weight compound obtained using a predetermined ester compound as a base resin is disclosed in JP3800318B. It is disclosed that the resist material exhibits high sensitivity and high resolution.

SUMMARY OF THE INVENTION

On the other hand, recently, high functionality of various electronic devices has been required, and thus, further improvement in characteristics of a resist composition used for microfabrication has correspondingly been required. In particular, further improvement in a depth of focus (DOF) has been required.

The present inventors have evaluated on the depth of focus using the resist material described in JP3800318B, and as a result, they have found that the obtained pattern cannot satisfy recently required levels, and thus, further improvements are required.

The present invention has been made in consideration of the above problems, and has an object to provide an actinic ray-sensitive or radiation-sensitive resin composition having an excellent depth of focus (DOF).

Furthermore, the present invention has another object to provide a pattern forming method, a method for manufacturing an electronic device, and an electronic device, each of which uses the composition.

The present inventors have conducted extensive studies on the problems in the related art, and as a result, they have found that the above problems can be solved by using an actinic ray-sensitive or radiation-sensitive resin composition including a resin including a predetermined functional group.

That is, the present inventors have found that the problems can be solved by the following configurations.

(1) An actinic ray-sensitive or radiation-sensitive resin composition comprising a resin (P) having a partial structure represented by General Formula (X), and a compound capable of generating an acid upon irradiation with actinic ray or radiation.

In General Formula (X), R₁ to R₃ each independently represent a hydrogen atom or an organic group, at least two of R₁ to R₃ are bonded to each other to form a ring structure, Z is a divalent alkylene group having 2 or more carbon atoms, and at least one of hydrogen atoms in the alkylene group is substituted with an organic group; the alkylene group may contain two or more of the organic groups, and a plurality of the organic groups may be bonded to each other to form a ring structure; and * represents a bonding position.

(2) The actinic ray-sensitive or radiation-sensitive resin composition as described in (1), in which the ring structure formed by the mutual bonding of at least two of R₁ to R₃ is a monocyclic cycloalkyl group.

(3) The actinic ray-sensitive or radiation-sensitive resin composition as described in (1) or (2), in which the organic group is an alkyl group.

(4) The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of (1) to (3), in which at least two of hydrogen atoms in the alkylene group are substituted with the organic group.

(5) The actinic ray-sensitive or radiation-sensitive resin composition as described in (4), in which the organic group is bonded to the same carbon atom in the alkylene group.

(6) A pattern forming method comprising at least:

(a) forming an actinic ray-sensitive or radiation-sensitive resin composition film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition as described in any one of (1) to (5),

(b) irradiating the film with actinic ray or radiation, and

(c) developing the film irradiated with actinic ray or radiation using a developer.

(7) The pattern forming method as described in (6), in which the developer is a developer including an organic solvent.

(8) A method for manufacturing an electronic device, comprising the pattern forming method as described in (6) or (7).

(9) An electronic device manufactured by the method for manufacturing an electronic device as described in (8).

According to the present invention, it is possible to provide an actinic ray-sensitive or radiation-sensitive resin composition having an excellent depth of focus (DOF).

In addition, according to the present invention, it is also possible to provide a pattern forming method, a method for manufacturing an electronic device, and an electronic device, each of which uses the composition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, suitable aspects of the present invention will be described in detail.

In citations for a group and an atomic group in the present specification, in the case where the group is denoted without specifying whether it is substituted or unsubstituted, the group includes both a group not having a substituent and a group having a substituent. For example, an “alkyl group” which is not denoted about whether it is substituted or unsubstituted includes not only an alkyl group not having a substituent (unsubstituted alkyl group), but also an alkyl group having a substituent (substituted alkyl group).

In the present invention, “actinic ray” or “radiation” means, for example, a bright line spectrum of a mercury lamp, far ultraviolet rays represented by an excimer laser, extreme ultraviolet rays (EUV light), X-rays, particle rays such as electron beams and ion beams, or the like. In addition, in the present invention, “light” means actinic ray or radiation.

Furthermore, “exposure” in the present specification includes, unless otherwise specified, not only exposure by a mercury lamp, far ultraviolet rays represented by an excimer laser, X-rays, extreme ultraviolet rays (EUV light), or the like, but also writing by particle rays such as electron beams and ion beams.

In the present specification, “(meth)acrylate” means “at least one of acrylate or methacrylate”.

The reason why desired effects of the actinic ray-sensitive or radiation-sensitive resin composition of the present invention (hereinafter also referred to as “the composition of the present invention” or “the resist composition of the present invention”) are obtained is not clear, but is presumed as follows.

The partial structure represented by General Formula (X) in the resin (P) included in the composition of the present invention includes a specific alicyclic group. Examples of the alicyclic group include a substituent such as an organic group. From this, it is presumed that an acid is supplied from a compound capable of generating an acid upon irradiation with actinic ray or radiation, which is used in combination with other components, and thus, volatilization hardly occurs when the substituent leaves from the resin skeleton, the plasticity of the actinic ray-sensitive or radiation-sensitive resin composition film is improved, and as a result, the depth of focus (DOF) is improved.

Hereinafter, the actinic ray-sensitive or radiation-sensitive resin composition of the present invention (hereinafter also referred to as “the composition of the present invention” or “the resist composition of the present invention”) will be described.

The composition of the present invention may be used in negative tone development (development in which an exposed area remains as a pattern and an unexposed area is removed), or in positive tone development (an exposed area is removed and an unexposed area remains as a pattern). That is, any one of a developer including an organic solvent and an alkali developer may be used to carry out the development.

Moreover, the composition of the present invention is typically a chemical amplification type resist composition.

The composition of the present invention includes at least:

[1] a resin (P) having a partial structure represented by General Formula (X) which will be described later and [2] a compound capable of generating an acid upon irradiation with actinic ray or radiation.

Examples of additional components which can be included in the composition according to the present invention include [3] a hydrophobic resin, [4] an acid diffusion control agent, [5] a solvent, and [6] a surfactant. The composition of the present invention can be used for pattern formation according to a method which will be described later as a “pattern forming method”, for example.

First, the respective components used in the composition will be sequentially described, and then a pattern forming method using the composition will be described in detail.

[1] Resin (P)

The composition of the present invention has a resin (P) having a partial structure represented by General Formula (X). Further, as described later, it is preferable that the resin (P) is typically a resin which has a change in polarity by the action of an acid and thus, has a change in solubility with respect to a developer.

In General Formula (X), R₁ to R₃ each independently represent a hydrogen atom or an organic group. The “organic group” means a functional group (for example, an alkyl group, a cycloalkyl group, an aryl group, and a group formed by a combination of these) containing at least one carbon atom, and may contain a hetero atom (for example, an oxygen atom).

Furthermore, in a suitable aspect of the organic group, in terms of superior depth of focus, an aliphatic hydrocarbon group is preferable, and an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms) is more preferable.

Moreover, at least two of R₁ to R₃ are bonded to each other to form a ring structure. Further, the ring structure includes at least two of R₁ to R₃ and carbon atoms (carbon atoms linked to R₁ to R₃).

Examples of the ring structure include an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aromatic heterocycle, or a polycyclic fused ring formed by a combination of two or more of these rings. Examples of the ring structure include 3- to 10-membered rings, with 4- to 8-membered rings being preferable, and 5- or 6-membered rings being more preferable.

Among these, as the ring structure, a monocyclic alicyclic structure, or a polycyclic alicyclic structure is preferable. The monocyclic alicyclic structure preferably contains 3 to 8 carbon atoms, more preferably 5 to 8 carbon atoms, still more preferably 5 or 6 carbon atoms, and particularly preferably 5 carbon atoms (further, the number of carbon atoms including the number of carbon atoms linked to R₁ to R₃). As the polycyclic alicyclic structure, a norbornyl group, a tetracyclodecanyl group, a tetracycloecanyl group, and an adamantyl group are preferable. In particular, as the ring structure, the monocyclic cycloalkyl group (a preferred range of the number of carbon atoms having the same definition as a suitable range of the number of carbon atoms described in the monocyclic alicyclic structure) is preferable. More specifically, suitable aspects of a case where the ring structure is a monocyclic cycloalkyl group include a partial structure represented by the following General Formula (V). Further, suitable aspects of a case where the ring structure is a polycyclic aliphatic structure include a partial structure represented by General Formula (P).

In General Formula (V), Z1 represents a divalent alkylene group having 2 or more carbon atoms, and the number of carbon atoms of the alkylene group is preferably 2 to 7, more preferably 4 to 7, still more preferably 4 or 5, and particularly preferably 4.

In General Formulae (V) and (P),

Z represents a divalent alkylene group having 2 or more carbon atoms. That is, Z forms a monocyclic cycloalkyl group, together with carbon atoms in General Formula (X).

The number of carbon atoms of the alkylene group is not particularly limited as long as it is 2 or more, but in terms of superior depth of focus, the alkylene group preferably has 4 to 7 carbon atoms, and more preferably has 4 or 5 carbon atoms.

Furthermore, at least one of hydrogen atoms in the alkylene group is substituted with an organic group. In other words, the alkylene group is represented by the following General Formula (Y). —(CR_(y1)R_(y2))_(n)—  General Formula (Y)

(In General Formula (Y), R_(y1) and R_(y2) each independently represent a hydrogen atom or an organic group, n represents an integer of 2 or more, and any one of a plurality of R_(y1)'s and R_(y2)'s represents an organic group.)

The definition of the organic group is the same as that of the organic groups represented by R₁ to R₃. Further, in terms of a superior depth of focus, an aliphatic hydrocarbon group is preferable, and an alkyl group is more preferable as the organic group.

At least one of hydrogen atoms in the alkylene group is substituted with an organic group, but two or more hydrogen atoms may be substituted with organic groups. Further, in terms of a superior depth of focus, in the case where two or more organic groups are bonded to the alkylene group (in the case where two or more hydrogen atoms out of hydrogen atoms in the alkylene group are substituted with an organic group), it is preferable that two organic groups are bonded to the same carbon atom in the alkylene group. In other words, it is preferable that R_(y1) and R_(y2) in at least one repeating unit out of the repeating units in the number of n or more included in General Formula (Y) are organic groups.

Incidentally, a plurality of organic groups may be bonded to each other to form a ring structure. The definition of the ring structure thus formed is the same as that of the ring structure formed by the mutual bonding of at least two of R₁ to R₃.

In General Formula (X), * represents a bonding position.

The partial structure represented by General Formula (X) may further be bonded to a divalent linking group. Examples of the divalent linking group include —COO—, —OCO—, —CONH—, —NHCO—, —CO—, —O—, —S—, —SO—, —SO₂—, an alkylene group (preferably having 1 to 6 carbon atoms), a cycloalkylene group (preferably having 3 to 10 carbon atoms), an alkenylene group (preferably having 2 to 6 carbon atoms), or a divalent linking group formed by a combination of a plurality of these groups. The linking group is bonded to * of the partial structure represented by General Formula (X). Also in the case where the partial structure represented by General Formula (X) is represented by General Formula (V) or (P), * in General Formula (V) or (P) may be bonded to a divalent linking group.

Suitable aspects of the partial structure represented by General Formula (X) include a partial structure represented by the following General Formula (Z), and more preferably a partial structure represented by General Formula (Z1) or (Z2).

The skeleton structure of the main chain of the resin (P) having a partial structure represented by General Formula (X) is not particularly limited, and examples thereof include a cycloolefin resin skeleton, a polyimide resin skeleton, an epoxy resin skeleton, a polyethylene resin skeleton, a polyester resin skeleton, a urethane resin skeleton, a novolac resin skeleton, a cresol resin skeleton, a (meth)acryl resin skeleton, and a styrene resin skeleton. Among these, in terms of easy synthesis and a superior depth of focus, a (meth)acryl resin skeleton ((meth)acryl main chain structure) is preferable.

The partial structure represented by General Formula (X) may be included as a side chain bonded to the main chain of the resin (P), or may be included as being bonded to a terminal. Preferably, the resin (P) having a repeating unit having the partial structure represented by General Formula (X) is preferable.

Among these, in terms of a superior depth of focus, the resin (P) is preferably a resin having a repeating unit represented by the following General Formula (W) (preferably a repeating unit represented by General Formula (W1) or (W2)).

The definitions of Z, and R₁ to R₃ in General Formulae (W) to General Formula (W2) are the same as those of Z, and R₁ to R₃ in General Formula (X).

In General Formulae (W) to General Formula (W2), R₄ represents a hydrogen atom or an alkyl group.

A method for synthesizing the resin (P) is not particularly limited, and the resin (P) can be synthesized by polymerization of monomers having the structure.

In addition, specific examples of the monomer which will become the repeating unit represented by General Formula (W) are shown below, but the present invention is not limited thereto.

The content of the repeating unit represented by General Formula (W) (or a repeating unit having the partial structure represented by General Formula (X)) in the resin (P) is not particularly limited, but it is preferably 5% by mole to 70% by mole, more preferably 10% by mole to 60% by mole, still more preferably 10% by mole to 40% by mole, and particularly preferably 10% by mole to 30% by mole, with respect to all the repeating units in the resin (P), in terms of a superior depth of focus.

The resin (P) is preferably a resin whose solubility with respect to a developer changes by decomposition by the action of an acid; more preferably a resin whose solubility with respect to an alkali developer increases by the action of an acid or whose solubility with respect to a developer having an organic solvent as a main component decreases by the action of an acid; and still preferably a resin having a group capable of decomposing by the action of an acid to generate an alkali-soluble group (hereinafter also referred to as an “acid-decomposable group”) on either one or both of the main chain and the side chain of the resin.

The resin (P) is preferably insoluble or sparingly soluble in an alkali developer.

The acid-decomposable group preferably has a structure in which an alkali-soluble group is protected with a group capable of leaving by the decomposition by the action of an acid.

Examples of the alkali-soluble group include a phenolic hydroxyl group, a carboxyl group, a fluorinated alcohol group, a sulfonic acid group, a sulfonamide group, a sulfonylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group, a bis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imide group, a tris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylene group.

Preferred examples of the alkali-soluble group include a carboxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), and a sulfonic acid group.

The group which is preferable as the acid-decomposable group is a group in which hydrogen atoms of these alkali-soluble groups are substituted with a group capable of leaving by an acid.

Examples of the group capable of leaving by an acid include —C(R₃₆)(R₃₇)(R₃₈), —C(R₃₆)(R₃₇)(OR₃₉), and —C(R₀₁)(R₀₂)(OR₃₉).

In the formulae, R₃₆ to R₃₉ each independently represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R₃₆ and R₃₇ may be bonded to each other to form a ring.

R₀₁ to R₀₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group.

The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group, or the like, and more preferably a tertiary alkyl ester group.

As the repeating unit having an acid-decomposable group which can be contained in the resin (P), a repeating unit represented by the following General Formula (AI) is preferable.

In General Formula (AI),

Xa₁ represents a hydrogen atom, or an alkyl group which may have a substituent,

T represents a single bond or a divalent linking group,

Rx₁ to Rx₃ each independently represent an (linear or branched) alkyl group or a (monocyclic or polycyclic) cycloalkyl group, and

two of Rx₁ to Rx₃ may be bonded to each other to form a (monocyclic or polycyclic) cycloalkyl group.

Examples of the alkyl group which may have a substituent, represented by Xa₁, include a methyl group or a group represented by —CH₂—R₁₁. R₁₁ represents a halogen atom (a fluorine atom or the like), a hydroxyl group, or a monovalent organic group, and examples thereof include an alkyl group having 5 or less carbon atoms, and an acyl group having 5 or less carbon atoms, preferably an alkyl group having 3 or less carbon atoms, and more preferably a methyl group. In one aspect, Xa₁ is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, a hydroxymethyl group, or the like.

Examples of the divalent linking group of T include an alkylene group, a —COO-Rt- group, and an —O-Rt- group. In the formulae, Rt represents an alkylene group or a cycloalkylene group.

T is preferably a single bond or a —COO-Rt- group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, and more preferably a —CH₂— group, a —(CH₂)₂— group, or a —(CH₂)₃— group.

As the alkyl group of Rx₁ to Rx₃, an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group is preferable.

As the cycloalkyl group of Rx₁ to Rx₃, a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, and a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferable.

As the cycloalkyl group formed by the mutual bonding of two members of Rx₁ to Rx₃, a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, and a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferable, and a monocyclic cycloalkyl group having 5 or 6 carbon atoms is particularly preferable.

In the cycloalkyl group formed by the mutual bonding of two members of Rx₁ to Rx₃, for example, one of the methylene groups constituting the ring may be substituted with a hetero atom such as an oxygen atom, or with a group having a hetero atom, such as a carbonyl group.

An aspect of the repeating unit represented by General Formula (AI), in which Rx₁ is a methyl group or an ethyl group, and Rx₂ and Rx₃ are bonded to each other to form the aforementioned cycloalkyl group, for example, is preferable.

Each of the groups may have a substituent, and examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms), with those having 8 or less carbon atoms being preferable.

The total content of the repeating unit having an acid-decomposable group is preferably 20% by mole to 90% by mole, more preferably 25% by mole to 85% by mole, and still more preferably 30% by mole to 80% by mole, with respect to all the repeating units in the resin (P).

Specific preferred examples of the repeating unit having an acid-decomposable group are shown below, but the present invention is not limited thereto.

In the specific examples, Rx and Xa₁ each represent a hydrogen atom, CH₃, CF₃, or CH₂OH. Rxa and Rxb each represent an alkyl group having 1 to 4 carbon atoms. Z represents a substituent containing a polar group, and in the case where Z's are present in plural numbers, they are each independent. p represents 0 or a positive integer. Examples of the substituent containing a polar group, represented by Z, include a linear or branched alkyl group, and a cycloalkyl group, each having a hydroxyl group, a cyano group, an amino group, an alkylamide group, or a sulfonamide group, and preferably an alkyl group having a hydroxyl group. As the branched alkyl group, an isopropyl group is particularly preferable.

It is preferable that the resin (P) contains, for example, a repeating unit represented by General Formula (3), as the repeating unit represented by General Formula (AI).

In General Formula (3),

R₃₁ represents a hydrogen atom or an alkyl group.

R₃₂ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a sec-butyl group,

R₃₃ represents an atomic group required for forming a monocyclic alicyclic hydrocarbon structure together with carbon atoms to which R₃₂ is bonded. In the alicyclic hydrocarbon structure, a part of the carbon atoms constituting the ring may be substituted with a hetero atom or a group having a hetero atom.

The alkyl group of R₃₁ may have a substituent, and examples of the substituent include a fluorine atom and a hydroxyl group. R₃₁ preferably represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

R₃₂ is preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and more preferably a methyl group or an ethyl group.

The monocyclic alicyclic hydrocarbon structure formed of R₃₃ together with carbon atoms is preferably a 3- to 8-membered ring, and more preferably a 5- or 6-membered ring.

In the monocyclic alicyclic hydrocarbon structure formed of R₃₃ together with carbon atoms, examples of the hetero atom which can constitute a ring include an oxygen atom and a sulfur atom, and examples of the group having a hetero atom include a carbonyl group. However, it is preferable that the group having a hetero atom is not an ester group (ester bond).

It is preferable that the monocyclic alicyclic hydrocarbon structure formed by R₃₃ together with carbon atoms is formed of only a carbon atom and a hydrogen atom.

The repeating unit represented by General Formula (3) is preferably a repeating unit represented by the following General Formula (3′).

In General Formula (3′), R₃₁ and R₃₂ each have the same definitions as those in General Formula (3).

Specific examples of the repeating unit having the structure represented by General Formula (3) are shown below, but are not limited thereto.

The content of the repeating units having the structure represented by General Formula (3) is preferably 20% by mole to 80% by mole, more preferably 25% by mole to 75% by mole, and still more preferably 30% by mole to 70% by mole, with respect to all the repeating units in the resin (P).

The resin (P) is more preferably a resin having at least one of the repeating unit represented by General Formula (I) or the repeating unit represented by General Formula (II), for example, as the repeating unit represented by General Formula (AI).

In Formulae (I) and (II),

R₁ and R₃ each independently represent a hydrogen atom, a methyl group which may have a substituent, or a group represented by —CH₂—R₁₁. R₁₁ represents a monovalent organic group.

R₂, R₄, R₅, and R₆ each independently represent an alkyl group or a cycloalkyl group.

R represents an atomic group required for forming an alicyclic structure together with carbon atoms.

R₁ and R₃ each preferably represent a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group. Specific examples of the monovalent organic group in R₁₁ and preferred examples thereof are the same groups as those described as R₁₁ in General Formula (AI).

The alkyl group in R₂ may be linear or branched, and may have a substituent.

The cycloalkyl group in R₂ may be monocyclic or polycyclic, and may have a substituent.

R₂ is preferably an alkyl group, more preferably an alkyl group having 1 to 10 carbon atoms, and still more preferably an alkyl group having 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, an isopropyl group, and a t-butyl group.

R represents an atomic group required for forming an alicyclic structure together with carbon atoms to which R₂ is bonded. As the alicyclic structure formed of R together with the carbon atom, a monocyclic alicyclic structure is preferable, and the number of carbon atoms is preferably 3 to 7, and more preferably 5 or 6.

R₃ preferably a hydrogen atom or a methyl group, and more preferably a methyl group.

The alkyl group in R₄, R₅, or R₆ may be linear or branched, and may have a substituent. As the alkyl group, an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group is preferable.

The cycloalkyl group in R₄, R₅, or R₆ may be monocyclic or polycyclic, and may have a substituent. As the cycloalkyl group, a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, and a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferable.

Examples of the substituent which each of the groups may have include those described above as the substituent which each of the groups in General Formula (AI) may have.

The acid-decomposable resin is more preferably a resin including the repeating unit represented by General Formula (I) and the repeating unit represented by General Formula (II) as the repeating unit represented by General Formula (AI).

Furthermore, in another embodiment, the acid-decomposable resin is more preferably a resin containing at least two repeating units represented by General Formula (I) as repeating unit represented by General Formula (AI). In the case where the acid-decomposable resin contains two or more repeating units of General Formula (I), it is preferable that acid-decomposable resin contains both of a repeating unit in which the alicyclic structure formed of R together with carbon atoms is a monocyclic alicyclic structure and a repeating unit in which the alicyclic structure formed of R together with carbon atoms is a polycyclic alicyclic structure. As the monocyclic alicyclic structure, the structure having 5 to 8 carbon atoms is preferable, the structure having 5 or 6 carbon atoms is more preferable, and the structure having 5 carbon atoms is particularly preferable. As the polycyclic alicyclic structure, a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferable.

The repeating units having an acid-decomposable group, which is contained in the resin (P), may be used alone or in combination of two or more kinds thereof. In the case of using the repeating units in combination, the combinations as mentioned below are preferable. In the following formulae, R's each independently represent a hydrogen atom or a methyl group.

The content of the repeating units containing an acid-decomposable group, which is included in the resin (P), which may be the total content of the repeating units in the case where two or more kinds of repeating units are contained, is preferably 30% by mole to 80% by mole, more preferably 40% by mole to 75% by mole, still more preferably 50% by mole to 70% by mole, and particularly preferably 55% by mole to 65% by mole, with respect to all the repeating units in the resin (P).

In one aspect, it is preferable that the resin (P) contains a repeating unit having a cyclic carbonic acid ester structure. This cyclic carbonic acid ester structure is a structure having a ring including a bond represented by —O—C(═O)—O— as an atomic group constituting the ring. The ring including a bond represented by —O—C(═O)—O— as an atomic group constituting the ring is preferably a 5- to 7-membered ring, and most preferably a 5-membered ring. Such a ring may be fused with another ring to form a fused ring.

It is preferable that the resin (P) contains a repeating unit having a lactone structure or a sultone (cyclic sulfonic acid ester) structure.

As the lactone group or the sultone group, any group may be used as long as it has a lactone structure or a sultone structure, but the structure is preferably a 5- to 7-membered ring lactone structure or sultone structure, and more preferably a 5- to 7-membered ring lactone structure or sultone structure to which another ring structure is fused in the form of forming a bicyclo structure or a spiro structure. The resin more preferably has a repeating unit having a lactone structure or a sultone structure represented by any one of the following General Formulae (LC1-1) to (LC1-17), (SL1-1), and (SL1-2). Further, the lactone structure or sultone structure may be bonded directly to the main chain. The lactone structure or sultone structure is preferably (LC1-1), (LC1-4), (LC1-5), or (LC1-8), and more preferably (LC1-4). By using such a specific lactone structure or sultone structure, LWR and development defects are relieved.

The lactone structure moiety or the sultone structure moiety may or may not have a substituent (Rb₂). Preferred examples of the substituent (Rb₂) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 2 to 8 carbon atoms, a carboxyl group, a halogen atom, a hydroxyl group, a cyano group, and an acid-decomposable group. Among these, an alkyl group having 1 to 4 carbon atoms, a cyano group, and an acid-decomposable group are more preferable. n₂ represents an integer of 0 to 4. When n₂ is 2 or more, the substituents (Rb₂) which are present in plural numbers may be the same as or different from each other, and further, the substituents (Rb₂) which are present in plural numbers may be bonded to each other to form a ring.

It is preferable that the resin (P) contains a repeating unit having a lactone structure or a sultone structure, represented by the following General Formula (III).

In Formula (III),

A represents an ester bond (a group represented by —COO—) or an amide bond (a group represented by —CONH—),

in the case where R₀'s are present in plural numbers, they each independently represent an alkylene group, a cycloalkylene group, or a combination thereof, and

in the case where Z's are present in plural numbers, they each independently represent a single bond, an ether bond, an ester bond, an amide bond, a urethane bond

or

an urea bond

Here, R's each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group.

R₈ represents a monovalent organic group having a lactone structure or a sultone structure.

n is the repetition number of the structure represented by —R₀—Z—, and represents an integer of 0 to 2.

R₇ represents a hydrogen atom, a halogen atom, or an alkyl group.

The alkylene group and the cycloalkylene group of R₀ may have a substituent.

Z is preferably an ether bond or an ester bond, and particularly preferably an ester bond.

The alkyl group of R₇ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group. The alkylene group and the cycloalkylene group of R₀, and the alkyl group in R₇ may be each substituted, and examples of the substituent include a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom, a mercapto group, a hydroxy group, an alkoxy group such as a methoxy group, an ethoxy group, an isopropoxy group, a t-butoxy group, and a benzyloxy group, and an acetoxy group such as an acetyloxy group and a propionyloxy group. R₇ is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

The preferred linear alkylene group in R₀ is linear alkylene, preferably having 1 to 10 carbon atoms, and more preferably having 1 to 5 carbon atoms, and examples thereof include a methylene group, an ethylene group, and a propylene group. Preferred examples of the cycloalkylene group include a cycloalkylene group having 3 to 20 carbon atoms, and examples thereof include a cyclohexylene group, a cyclopentylene group, a norbornylene group, and an adamantylene group. In order to express the effects of the present invention, a linear alkylene group is more preferable, and a methylene group is particularly preferable.

The monovalent organic group having a lactone structure or a sultone structure represented by R₈ is not limited as long as it has a lactone structure or a sultone structure. Specific examples thereof include ones having lactone structures or sultone structures represented by General Formulae (LC1-1) to (LC1-17), (SL1-1), and (SL1-2), and the structure represented by (LC1-4) is particularly preferable. Further, n₂ in (LC1-1) to (LC1-17), (SL1-1), and (SL1-2) is more preferably 2 or less.

Furthermore, R₈ is preferably a monovalent organic group having an unsubstituted lactone structure or sultone structure, or a monovalent organic group having a lactone structure or a sultone structure having a methyl group, a cyano group, or an alkoxycarbonyl group as a substituent, and more preferably a monovalent organic group having a lactone structure having a cyano group as a substituent (cyanolactone) or a sultone structure having a cyano group as a substituent (cyanosultone).

In General Formula (III), n is preferably 1 or 2.

Specific examples of the repeating unit having a group having the lactone structure or sultone structure represented by General Formula (III) are shown below, but the present invention is not limited thereto.

In the following specific examples, R represents a hydrogen atom, an alkyl group which may have a substituent, or a halogen atom, and preferably represents a hydrogen atom, a methyl group, a hydroxymethyl group, or an acetoxymethyl group.

In the following formulae, Me represents a methyl group.

As the repeating unit having a lactone structure or a sultone structure, a repeating unit represented by the following General Formula (III-1) or (III-1′) is more preferable.

In General Formulae (III-1) and (III-1′),

R₇, A, R₀, Z, and n have the same definitions as in those General Formula (III).

R₇′, A′, R₀′, Z′, and n′ each have the same definitions R₇, A, R₀, Z, and n in General Formula (III).

In the case where R₉′s are present in plural numbers, they each independently represent an alkyl group, a cycloalkyl group, an alkoxycarbonyl group, a cyano group, a hydroxyl group, or an alkoxy group, and in the case where they are present in plural numbers, two R₉'s may be bonded to each other to form a ring.

In the case where R₉'s are present in plural numbers, they each independently represent an alkyl group, a cycloalkyl group, an alkoxycarbonyl group, a cyano group, a hydroxyl group, or an alkoxy group, and in the case where they are present in plural numbers, two R₉'s may be bonded to each other to form a ring.

X and X′ each independently represent an alkylene group, an oxygen atom, or a sulfur atom.

m and m′ are each the number of substituents, and each independently represent an integer of 0 to 5. m and m′ are each independently preferably 0 or 1.

As the alkyl group of R₉ and R₉′, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group and an ethyl group are more preferable, and a methyl group is most preferable. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group, and a t-butoxycarbonyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a butoxy group. These groups may have a substituent, and examples of the substituent include an alkoxy group such as a hydroxy group, a methoxy group, and an ethoxy group, a cyano group, and a halogen atom such as a fluorine atom. R₉ and R₉′ are each more preferably a methyl group, a cyano group, or an alkoxycarbonyl group, and still more preferably a cyano group.

Examples of the alkylene group of X and X′ include a methylene group and an ethylene group. X and X′ are preferably an oxygen atom or a methylene group, and more preferably a methylene group.

In the case where m and m′ are 1 or more, at least one of R₉ or R₉′ is preferably substituted at the α- or β-position of the carbonyl group of the lactone, and particularly preferably at the α-position.

Specific examples of the group having a lactone structure or the repeating unit having a sultone structure, represented by General Formula (III-1) or (III-1′), are shown, but the present invention is not limited thereto. In the following specific examples, R represents a hydrogen atom, an alkyl group which may have a substituent, or a halogen atom, and preferably represents a hydrogen atom, a methyl group, a hydroxymethyl group, or an acetoxymethyl group.

The content of the repeating unit represented by General Formula (III), which may be the total content of the repeating units in the case where two or more kinds of repeating units, are contained is preferably 15% by mole to 60% by mole, more preferably 20% by mole to 60% by mole, and still more preferably 30% by mole to 50% by mole, with respect to all the repeating units in the resin (P).

The resin (P) may further contain, in addition to the unit represented by General Formula (III), the aforementioned repeating unit having a lactone structure or a sultone structure.

Specific examples of the repeating unit having a lactone group or sultone group are shown below in addition to the aforementioned specific examples, but the present invention is not limited thereto.

Among the specific examples, particularly preferred examples of the repeating units include the following repeating units. By selecting an optimal lactone group or sultone group, the pattern profile and the density dependence are improved.

The repeating unit having a lactone group or sultone group usually has an optical isomer, and any optical isomer may be used. Further, one kind of optical isomer may be used alone or a plurality of optical isomers may be mixed and used. In the case of mainly using one kind of optical isomer, the optical purity (ee) thereof is preferably 90% or more, and more preferably 95% or more.

The content of the repeating unit having a lactone structure or a sultone structure, other than the repeating unit represented by General Formula (III), which may be the total content of the repeating units in the case where two or more kinds of repeating units are contained, is preferably 15% by mole to 60% by mole, more preferably 20% by mole to 50% by mole, and still more preferably 30% by mole to 50% by mole, with respect to all the repeating units in the resin.

In order to enhance the effect of the present invention, it is also possible to use two or more kinds of lactone or sultone repeating units selected from General Formula (III) in combination. In the case of using the repeating units in combination, it is preferable to use two or more kinds selected from the lactone or sultone repeating units, in which in n is 1 in General Formula (III), in combination.

It is preferable that the resin (P) has a repeating unit having a hydroxyl group or a cyano group, other than General Formulae (AI) and (III). With the repeating unit, the adhesion to a substrate and the developer affinity are enhanced. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and preferably has no acid-decomposable group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group. As the alicyclic hydrocarbon structures substituted with a hydroxyl group or a cyano group, partial structures represented by the following General Formulae (VIIa) to (VIId) are preferable.

In General Formulae (VIIa) to (VIIc),

R₂c to R₄c each independently represent a hydrogen atom, a hydroxyl group, or a cyano group, provided that at least one of R₂c to R₄c represents a hydroxyl group or a cyano group. It is preferable that one or two of R₂c to R₄c are a hydroxyl group and the remainders are a hydrogen atom. In General Formula (VIIa), it is more preferable that two of R₂c to R₄c are a hydroxyl group and the remainder is a hydrogen atom.

Examples of the repeating unit having a partial structure represented by General Formulae (VIIa) to (VIId) include repeating units represented by the following General Formulae (AIIa) to (AIId).

In General Formulae (AIIa) to (AIId),

R₁c represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group, and

R₂c to R₄c have the same meanings as R₂c to R₄c in General Formulae (VIIa) to (VIIc).

The content of the repeating units having a hydroxyl group or a cyano group is preferably 5% by mole to 40% by mole, more preferably 5% by mole to 30% by mole, and still more preferably 10% by mole to 25% by mole, with respect to all the repeating units in the resin (P).

Specific examples of the repeating unit having a hydroxyl group or a cyano group are shown below, but the present invention is not limited thereto.

The resin (P) used in the composition of the present invention may have a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulfonylimide group, and an aliphatic alcohol with the α-position being substituted with an electron-withdrawing group (for example, a hexafluoroisopropanol group). It is more preferable to contain a repeating unit having a carboxyl group. By virtue of containing a repeating unit having an alkali-soluble group, the resolution increases in the usage of forming contact holes. As the repeating unit having an alkali-soluble group, all of a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit by an acrylic acid or a methacrylic acid, a repeating unit in which an alkali-soluble group is bonded to the main chain of the resin through a linking group, and a repeating unit in which an alkali-soluble group is introduced into the polymer chain terminal by using an alkali-soluble group-containing polymerization initiator or a chain transfer agent at the polymerization, are preferable. The linking group may have a monocyclic or polycyclic hydrocarbon structure. A repeating unit by an acrylic acid or a methacrylic acid is particularly preferable.

The content of the repeating units having an alkali-soluble group is preferably 0% by mole to 20% by mole, more preferably 3% by mole to 15% by mole, and still more preferably 5% by mole to 10% by mole, with respect to all the repeating units in the resin (P).

Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto.

In the specific examples, Rx represents H, CH₃, CH₂OH, or CF₃.

The resin (P) may further have a repeating unit which has an alicyclic hydrocarbon structure not having a polar group (for example, an alkali-soluble group, a hydroxyl group, and a cyano group) and does not exhibit acid decomposability. Examples of such a repeating unit include a repeating unit represented by General Formula (IV).

In General Formula (IV), R₅ represents a hydrocarbon group having at least one cyclic structure and not having a polar group.

Ra represents a hydrogen atom, an alkyl group, or a —CH₂—O—Ra₂ group. In the formula, Ra₂ represents a hydrogen atom, an alkyl group, or an acyl group. Ra₂ is preferably a hydrogen atom, a methyl group, a hydroxymethyl group, or a trifluoromethyl group, and particularly preferably a hydrogen atom or a methyl group.

The cyclic structure contained in R₅ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include a cycloalkyl group having 3 to 12 carbon atoms, such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group, and a cycloalkenyl group having 3 to 12 carbon atoms, such as a cyclohexenyl group. A preferred monocyclic hydrocarbon group is a monocyclic hydrocarbon group having 3 to 7 carbon atoms, and more preferred examples thereof include a cyclopentyl group and a cyclohexyl group.

Examples of the polycyclic hydrocarbon group include a ring-assembly hydrocarbon group and a crosslinked cyclic hydrocarbon group. Examples of the ring-assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group, and examples of the crosslinked cyclic hydrocarbon ring include bicyclic hydrocarbon rings such as a pinane ring, a bornane ring, a norpinane ring, a norbornane ring, and a bicyclooctane ring (a bicyclo[2.2.2]octane ring, a bicyclo[3.2.1]octane ring, or the like); tricyclic hydrocarbon rings such as a homobledane ring, an adamantane ring, a tricyclo[5.2.1.0^(2,6)]decane ring, and a tricyclo[4.3.1.1^(2,5)]undecane ring; and tetracyclic hydrocarbon rings such as a tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecane ring and a perhydro-1,4-methano-5,8-methanonaphthalene ring. Other examples of the crosslinked cyclic hydrocarbon ring include fused cyclic hydrocarbon rings, and more specifically fused rings formed by fusing a plurality of 5- to 8-membered cycloalkane rings, such as a perhydronaphthalene (decalin) ring, a perhydroanthracene ring, a perhydrophenanthrene ring, a perhydroacenaphthene ring, a perhydrofluorene ring, a perhydroindene ring, and a perhydrophenalene ring.

Preferred examples of the crosslinked cyclic hydrocarbon ring include a norbornyl group, an adamantyl group, a bicyclooctanyl group, and a tricyclo[5,2,1,0^(2,6)]decanyl group. More preferred examples of the crosslinked cyclic hydrocarbon rings include a norbornyl group and an adamantyl group.

The alicyclic hydrocarbon groups may have a substituent, and preferred examples of the substituent include a halogen atom, an alkyl group, a hydroxyl group with a hydrogen atom being substituted, and an amino group with a hydrogen atom being substituted. Preferred examples of the halogen atom include a bromine atom, a chlorine atom, and a fluorine atom, and preferred examples of the alkyl group include a methyl group, an ethyl group, a butyl group, and a t-butyl group. The alkyl group may further have a substituent, and examples of the substituent, which the alkyl group may further have, may include a halogen atom, an alkyl group, a hydroxyl group with a hydrogen atom being substituted, and an amino group with a hydrogen atom being substituted.

Examples of the group with a hydrogen atom being substituted include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group. Preferred examples of the alkyl group include an alkyl group having 1 to 4 carbon atoms, preferred examples of the substituted methyl group include a methoxymethyl group, a methoxythiomethyl group, a benzyloxymethyl group, a t-butoxymethyl group, and a 2-methoxyethoxymethyl group, examples of the substituted ethyl group include a 1-ethoxyethyl group and a 1-methyl-1-methoxyethyl group, preferred examples of the acyl group include an aliphatic acyl group having 1 to 6 carbon atoms, such as a formyl group, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, and a pivaloyl group, and examples of the alkoxycarbonyl group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

The resin (P) may or may not contain a repeating unit which has an alicyclic hydrocarbon structure not having a polar group and does not exhibit acid decomposability, but in the case where the resin (P) contains the repeating unit, the content of the repeating unit is preferably 1% by mole to 40% by mole, and more preferably 2% by mole to 20% by mole, with respect to all the repeating units in the resin (P).

Specific examples of the repeating unit which has an alicyclic hydrocarbon structure not having a polar group and does not exhibit acid decomposability are shown below, but the present invention is not limited thereto. In the formulae, Ra represents H, CH₃, CH₂OH, or CF₃.

The resin (P) may contain a repeating unit represented by the following General Formula (nI) or (nII).

In General Formulae (nI) and (nII),

R₁₃′ to R₁₆′ each independently represent a hydrogen atom, a halogen atom, a cyano group, a hydroxyl group, a carboxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, a group having a lactone structure, or a group having an acid-decomposable group,

X₁ and X₂ each independently represent a methylene group, an ethylene group, an oxygen atom, or a sulfur atom, and

n represents an integer of 0 to 2.

Examples of the acid-decomposable group having an acid-decomposable group as R₁₃′ to R₁₆′ include a cumyl ester group, an enol ester group, an acetal ester group, and a tertiary alkyl ester group, and the acid-decomposable group is preferably a tertiary alkyl ester group represented by —C(═O)—O—R₀.

In the formula, R₀ represents a tertiary alkyl group such as a t-butyl group and a t-amyl group, an isobornyl group, a 1-alkoxyethyl group such as a 1-ethoxyethyl group, a 1-butoxyethyl group, a 1-isobutoxyethyl group, and a 1-cyclohexyloxyethyl group, an alkoxymethyl group such as a 1-methoxymethyl group and a 1-ethoxymethyl group, a 3-oxoalkyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, a trialkylsilyl ester group, a 3-oxocyclohexyl ester group, a 2-methyl-2adamantyl group, and a mevalonic lactone residue.

At least one of R₁₃′ to R₁₆′ is preferably a group having an acid-decomposable group.

Examples of the halogen atom in R₁₃′ to R₁₆′ include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

The alkyl group of R₁₃′ to R₁₆′ is more preferably a group represented by the following General Formula (F1).

In General Formula (F1),

R₅₀ to R₅₅ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group, provided that at least one of R₅₀ to R₅₅ represents a fluorine atom or an alkyl group having at least one hydrogen atom substituted with a fluorine atom; and

Rx represents a hydrogen atom or an organic group (preferably an acid-decomposable protecting group, an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group), and preferably a hydrogen atom.

It is preferable that all of R₅₀ to R₅₅ are fluorine atoms.

Examples of the repeating unit represented by General Formula (nI) or General Formula (nII) include the following specific examples, but the present invention is not limited to these compounds. Among those, repeating units represented by (II-f-16) to (II-f-19) are preferable.

In addition to the repeating structural units, the resin (P) used in the composition of the present invention can have a variety of repeating structural units for the purpose of adjusting dry etching resistance, suitability for a standard developer, adhesion to a substrate, and a resist profile, and in addition, resolving power, heat resistance, sensitivity, and the like, which are characteristics generally required for the resist. Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thus, it becomes possible to perform fine adjustments to performance required for the resin used in the composition of the present invention, in particular, (1) solubility with respect to a coating solvent, (2) film-forming properties (glass transition point), (3) alkali developability, (4) film reduction (selection of hydrophilic, hydrophobic, or alkali-soluble groups), (5) adhesion of an unexposed area to a substrate, (6) dry etching resistance, and the like.

Examples of such a monomer include a compound having one addition-polymerizable unsaturated bond selected from acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, and vinyl esters.

In addition to these, an addition-polymerizable unsaturated compound that is copolymerizable with the monomers corresponding to various repeating structural units as described above may be copolymerized.

In the resin (P) used in the composition of the present invention, the molar ratio of each repeating structural unit content is appropriately set in order to adjust dry etching resistance, suitability for a standard developer, adhesion to a substrate, and a resist profile of the resist, and in addition, resolving power, heat resistance, sensitivity, and the like, each of which is performance generally required for the resist.

When the composition of the present invention is for ArF exposure, it is preferable that the resin (P) used in the composition of the present invention has substantially no aromatic groups in terms of transparency to ArF light. More specifically, the proportion of repeating units having an aromatic group in all the repeating units of the resin (P) is preferably 5% by mole or less, more preferably 3% by mole or less, and ideally 0% by mole of all the repeating units, that is, it is more preferable that the resin (P) does not have a repeating unit having an aromatic group. In addition, it is preferable that the resin (P) has a monocyclic or polycyclic alicyclic hydrocarbon structure.

In the case of irradiating the composition of the present invention with KrF excimer laser light, electron beams, X-rays, or high-energy beams at a wavelength of 50 nm or less (for example, EUV), it is preferable that the resin (P) contains a hydroxystyrene repeating unit. The resin (P) is more preferably a copolymer of hydroxystyrene with hydroxystyrene protected with a group capable of leaving by the action of an acid, or a copolymer of hydroxystyrene with tertiary alkyl (meth)acrylate ester.

Specific examples of such a resin include a resin having a repeating unit represented by the following General Formula (A).

In the formula, R₀₁, R₀₂, and R₀₃ each independently represent, for example, a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group, or an alkoxycarbonyl group. Ar₁ represents, for example, an aromatic ring group. Further, R₀₃ and Ar₁ are each an alkylene group, or both of them may be bonded to each other, together with a —C—C— chain, to form a 5- or 6-membered ring.

Y's in the number of n each independently represent a hydrogen atom or a group capable of leaving by an action of an acid, provided that at least one of Y's represents a group capable of leaving by an action of an acid.

n represents an integer of 1 to 4, and is preferably 1 or 2, and more preferably 1.

The alkyl group as R₀₁ to R₀₃ is, for example, preferably an alkyl group having 20 or less carbon atoms, preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, or a dodecyl group, and more preferably an alkyl group having 8 or less carbon atoms. Further, these alkyl groups may have substituents.

The alkyl group included in the alkoxycarbonyl group is preferably the same as the alkyl group in R₀₁ to R₀₃

The cycloalkyl group may be a monocyclic cycloalkyl group or a polycyclic cycloalkyl group. Preferred examples thereof include a monocyclic cycloalkyl group having 3 to 8 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group. Here, these cycloalkyl groups may have a substituent.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is more preferable.

In the case where R₀₃ represents an alkylene group, preferred examples of the alkylene group include ones having 1 to 8 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, and an octylene group.

The aromatic ring group as Ar₁ is preferably one having 6 to 14 carbon atoms, and examples thereof include a benzene ring, a toluene ring, and a naphthalene ring. Here, these aromatic ring groups may have a substituent.

Examples of the group Y capable of leaving by an action of an acid include a group represented by —C(R₃₆)(R₃₇)(R₃₈), —C(═O)—O—C(R₃₆)(R₃₇)(R₃₈), —C(R₀₁)(R₀₂)(OR₃₉), —C(R₀₁)(R₀₂)—C(═O)—O—C(R₃₆)(R₃₇)(R₃₈), or —CH(R₃₆)(Ar).

In the formula, R₃₆ to R₃₉ each independently represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R₃₆ and R₃₇ may be bonded to each other to form a ring structure.

R₀₁ and R₀₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group.

Ar represents an aryl group.

As the alkyl group as R₃₆ to R₃₉, R₀₁, or R₀₂, an alkyl group having 1 to 8 carbon atoms is preferable and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a hexyl group, and an octyl group.

A cycloalkyl group as R₃₆ to R₃₉, R₀₁, or R₀₂ may be a monocyclic cycloalkyl group or a polycyclic cycloalkyl group. As the monocyclic cycloalkyl group, a cycloalkyl group having 3 to 8 carbon atoms is preferable, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and cyclooctyl group. As the polycyclic cycloalkyl group, a cycloalkyl group having 6 to 20 carbon atoms is preferable, and examples thereof include an adamantyl group, a norbornyl group, an isobornyl group, a camphonyl group, a dicyclopentyl group, an α-pinanyl group, a tricyclodecanyl group, a tetracyclododecyl group, and an androstanyl group. Further, some of the carbon atoms in the cycloalkyl group may be substituted with hetero atoms such as an oxygen atom.

An aryl group as R₃₆ to R₃₉, R₀₁, R₀₂, or Ar is preferably an aryl group having 6 to 10 carbon atoms and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.

An aralkyl group as R₃₆ to R₃₉, R₀₁, or R₀₂ is preferably an aralkyl group having 7 to 12 carbon atoms and for example, a benzyl group, a phenethyl group, and a naphthylmethyl group are preferable.

An alkenyl group as R₃₆ to R₃₉, R₀₁, or R₀₂ is preferably an alkenyl group having 2 to 8 carbon atoms and examples thereof include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.

A ring which can be formed by the mutual bonding of R₃₆ and R₃₇ may be monocyclic or may be polycyclic. As the monocyclic ring, a cycloalkane structure having 3 to 8 carbon atoms is preferable, and examples thereof include a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, and a cyclooctane structure. As the polycyclic ring, a cycloalkane structure having 6 to 20 carbon atoms is preferable, and examples thereof include an adamantane structure, a norbornane structure, a dicyclopentane structure, a tricyclodecane structure, and a tetracyclododecane structure. Further, a part of the carbon atoms in the ring structure may be substituted with hetero atoms such as an oxygen atom.

Each of the groups described above may have a substituent. Examples of the substituent include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a cyano group, and a nitro group. These substituents preferably have 8 or less carbon atoms.

As a group Y capable of leaving by an action of an acid, a structure represented by the following General Formula (B) is more preferable.

In the formula, L₁ and L₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group,

M represents a single bond or a divalent linking group, and

Q represents an alkyl group, a cycloalkyl group, a cyclic aliphatic group, an aromatic ring group, an amino group, an ammonium group, a mercapto group, a cyano group, or an aldehyde group. Further, these cyclic aliphatic groups and aromatic ring groups may include hetero atoms.

Furthermore, at least two of Q, M, or L₁ may be bonded to each other to form a 5- or 6-membered ring.

An alkyl group as L₁ and L₂ is, for example, an alkyl group having 1 to 8 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a hexyl group, and an octyl group.

A cycloalkyl group as L₁ and L₂ is, for example, a cycloalkyl group having 3 to 15 carbon atoms, and specific examples thereof include a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.

An aryl group as L₁ and L₂ is, for example, an aryl group having 6 to 15 carbon atoms, and specific examples thereof include a phenyl group, a tolyl group, a naphthyl group, and an anthryl group.

An aralkyl group as L₁ and L₂ is, for example, an aralkyl group having 6 to 20 carbon atoms, and specific examples thereof include a benzyl group and a phenethyl group.

A divalent linking group as M is, for example, an alkylene group (for example, a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, or an octylene group), a cycloalkylene group (for example, a cyclopentylene group or a cyclohexylene group), an alkenylene group (for example, an ethylene group, a propenylene group, or a butenylene group), an arylene group (for example, a phenylene group, a tolylene group, or a naphthylene group), —S—, —O—, —CO—, —SO₂—, —N(R₀)—, and a combination of two or more thereof. Here, R₀ is a hydrogen atom or an alkyl group. The alkyl group as R₀ is, for example, an alkyl group having 1 to 8 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a hexyl group, and an octyl group.

The alkyl group and the cycloalkyl group as Q are the same as each group as L₁ and L₂ described above.

Examples of the cyclic aliphatic group or the aromatic ring group as Q include the cycloalkyl group and the aryl group as L₁ and L₂ described above. The cycloalkyl group and the aryl group are preferably groups having 3 to 15 carbon atoms.

Examples of the cyclic aliphatic group or the aromatic ring group, containing a hetero atom, as Q include groups such as thiirane, cyclothiolane, thiophene, furan, pyrrole, benzothiophene, benzofuran, benzopyrrole, triazine, imidazole, benzimidazole, triazole, thiadiazole, thiazole, pyrrolidone, and the like which have a heterocyclic structure. However, the cyclic aliphatic group or the aromatic ring group is not limited thereto as long as it is a ring which is formed by carbon and hetero atoms or a ring which is formed by only hetero atoms.

Examples of a ring structure which at least two of Q, M, or L₁ may form by being bonded to each other include a 5- or 6-membered ring structure which is formed by these forming a propylene group or a butylene group. Here, the 5- or 6-membered ring structure contains an oxygen atom.

Each of the groups represented by L₁, L₂, M, and Q in General Formula (B) may have a substituent. Examples of the substituent include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a cyano group, and a nitro group. The substituents preferably have 8 or less carbon atoms.

As a group represented by -(M-Q), a group having 1 to 20 carbon atoms is preferable, a group having 1 to 10 carbon atoms is more preferable, and a group having 1 to 8 carbon atoms is still more preferable.

In these specific examples, tBu represents a t-butyl group.

Furthermore, it is preferable that the resin (P) contains neither a fluorine atom nor a silicon atom from the viewpoint of compatibility with a hydrophobic resin (D) which will be described later.

The resin (P) used in the composition of the present invention is preferably a resin in which all the repeating units are composed of (meth)acrylate-based repeating units. In this case, any one of a resin in which all the repeating units are methacrylate-based repeating units, a resin in which all the repeating units are acrylate-based repeating units, or a resin in which all the repeating units are composed of methacrylate-based repeating units and acrylate-based repeating units can be used, but the acrylate-based repeating units preferably accounts for 50% by mole or less with respect to all the repeating units. Further, a copolymerization polymer including 20% by mole to 50% by mole of a (meth)acrylate-based repeating unit having an acid-decomposable group, 20% by mole to 50% by mole of a (meth)acrylate-based repeating unit having a lactone group, and 5% by mole to 30% by mole of a (meth)acrylate-based repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or cyano group, and in addition to these, 0% by mole to 20% by mole of other (meth)acrylate-based repeating units are also preferable.

The resin (P) in the present invention can be synthesized in accordance with an ordinary method (for example, radical polymerization). Examples of the general synthesis method include a bulk polymerization method in which polymerization is carried out by dissolving monomer species and an initiator in a solvent and heating the solution, a dropwise addition polymerization method in which a solution of monomer species and an initiator is added dropwise to a heating solvent for 1 hour to 10 hours, with the dropwise addition polymerization method being preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, and diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethyl formamide and dimethyl acetamide, and a solvent which dissolves the composition of the present invention, such as propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone, which will be described later. It is more preferable to perform polymerization using the same solvent as the solvent used in the composition of the present invention. Thus, generation of the particles during storage can be inhibited.

It is preferable that the polymerization reaction is carried out in an inert gas atmosphere such as nitrogen and argon. As the polymerization initiator, commercially available radical initiators (an azo-based initiator, peroxide, or the like) are used to initiate the polymerization. As the radical initiator, an azo-based initiator is preferable, and the azo-based initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferable initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis(2-methyl propionate), or the like. The initiator is added or added in portionwise, as desired, a desired polymer is recovered after the reaction is completed, the reaction mixture is poured into a solvent, and then a method such as powder or solid recovery is used. The concentration at the reactant is 5% by mass to 50% by mass and preferably 10% by mass to 30% by mass. The reaction temperature is normally 10° C. to 150° C., preferably 30° C. to 120° C., and more preferably 60° C. to 100° C.

The weight-average molecular weight of the resin (P) of the present invention is preferably 1,000 to 200,000, more preferably 2,000 to 20,000, still more preferably 3,000 to 15,000, and particularly preferably 3,000 to 11,000 as a polystyrene-value by means of GPC. By setting the weight-average molecular weight to 1,000 to 200,000, it is possible to prevent the deterioration of heat resistance or dry etching resistance, and also prevent the deterioration of film forming properties due to deterioration of developability or increased viscosity.

The dispersity (molecular weight distribution: Mw/Mn) to be used is usually in the range of 1.0 to 3.0, preferably 1.0 to 2.6, more preferably 1.0 to 2.0, and particularly preferably 1.1 to 2.0. The smaller the molecular weight distribution is, the better the resolution and the resist shape are, the smoother the side wall of the resist pattern is, and the better roughness is.

The content of the resin (P) in the entire composition is preferably 30% by mass to 99% by mass, and more preferably 50% by mass to 95% by mass, with respect to the total solid contents.

Furthermore, the resin (P) may be used alone or in combination of two or more kinds thereof.

[2] Compound Capable of Generating Acid Upon Irradiation with Actinic Ray or Radiation

Usually, the actinic ray-sensitive or radiation-sensitive resin composition used in the present invention preferably further includes a compound (B) capable of generating an acid upon irradiation with actinic ray or radiation (hereinafter also referred to as an “acid generator” or a “compound (B)”). As the compound (B) capable of generating an acid upon irradiation with actinic ray or radiation, a compound capable of generating an organic acid upon irradiation with actinic ray or radiation is preferable. Further, the compound (B) may be included in the aforementioned resin (P). More specifically, the compound (B) may be linked to the resin (P) via a chemical bond.

The compound (B) may be in a form of a low-molecular-weight compound or in a form in which the compound (B) is introduced into a part of a polymer. Further, a combination of the form of a low-molecular-weight compound and the form introduced into a part of a polymer may also be used.

In the case where the compound (B) is in the form of a low-molecular-weight compound, the molecular weight is preferably 3,000 or less, more preferably 2,000 or less, and still more preferably 1,000 or less.

In the case where the compound (B) is in the form in which the compound (B) is introduced into a part of a polymer, it may be introduced into a part of the aforementioned resin (P) or into a resin other than the resin (P). Specific examples of the case where the compound (B) is in the form in which the compound (B) is introduced into a part of a polymer include those described in, for example, paragraphs “0191” to “0209” of JP2013-54196A.

The acid generator which can be used may be appropriately selected from a photoinitiator for cationic photopolymerization, a photoinitiator for radical photopolymerization, a photodecoloring agent for dyes, a photodiscoloring agent, a known compound capable of generating an acid upon irradiation with actinic ray or radiation, which is used for a microresist or the like, and a mixture thereof.

Examples of the acid generator include a diazonium salt, a phosphonium salt, a sulfonium salt, an iodonium salt, imidesulfonate, oxime sulfonate, diazodisulfone, disulfone, and o-nitrobenzyl sulfonate.

Preferred examples of the compounds among the acid generators include compounds represented by the following General Formulae (ZI), (ZII), and (ZIII).

In General Formula (ZI),

R₂₀₁, R₂₀₂, and R₂₀₃ each independently represent an organic group,

the number of carbon atoms of the organic group as R₂₀₁, R₂₀₂, and R₂₀₃ is generally 1 to 30, and preferably 1 to 20,

two of R₂₀₁ to R₂₀₃ may be bonded to each other to form a ring structure, and the ring may include an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group, and examples of the group formed by the mutual bonding of two of R₂₀₁ to R₂₀₃ include an alkylene group (for example, a butylene group and a pentylene group), and

Z⁻ represents a non-nucleophilic anion.

Examples of the non-nucleophilic anion as Z⁻ include a sulfonic acid anion, a carboxylic acid anion, a sulfonylimide anion, a bis(alkylsulfonyl)imide anion, and a tris(alkylsulfonyl)methyl anion.

The non-nucleophilic anion is an anion having an extremely low ability of causing a nucleophilic reaction and this anion can suppress the decomposition with aging due to an intramolecular nucleophilic reaction. With this anion, the stability over time of the composition is improved.

Examples of the sulfonic acid anion include an aliphatic sulfonic acid anion, an aromatic sulfonic acid anion, and a camphorsulfonic acid anion.

Examples of the carboxylic acid anion include an aliphatic carboxylic acid anion, an aromatic carboxylic acid anion, and an aralkylcarboxylic acid anion.

The aliphatic moiety in the aliphatic sulfonic acid anion and the aliphatic carboxylic acid anion may be an alkyl group, or a cycloalkyl group, and preferred examples thereof include an alkyl group having 1 to 30 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms and preferred examples of the aromatic group in the aromatic sulfonic acid anion and the aromatic carboxylic acid anion include an aryl group having 6 to 14 carbon atoms, for example, a phenyl group, a tolyl group, and a naphthyl group.

The alkyl group, the cycloalkyl group, and the aryl group in the aliphatic sulfonic acid anion and the aromatic sulfonic acid anion may have a substituent.

Examples of other non-nucleophilic anions include fluorinated phosphorus (for example, PF₆ ⁻), fluorinated boron (for example, BF₄ ⁻), and fluorinated antimony (for example, SbF₆ ⁻).

The non-nucleophilic anion of Z⁻ is preferably an aliphatic sulfonic acid anion substituted with a fluorine atom at least at the α-position of sulfonic acid, an aromatic sulfonic acid anion substituted with a fluorine atom or a group having a fluorine atom, a bis(alkylsulfonyl)imide anion in which the alkyl group is substituted with a fluorine atom, or a tris(alkylsulfonyl)methide anion in which the alkyl group is substituted with a fluorine atom. The non-nucleophilic anion is more preferably a perfluoroaliphatic sulfonic acid anion having 4 to 8 carbon atoms or a benzenesulfonic acid anion having a fluorine atom, and still more preferably a nonafluorobutanesulfonic acid anion, a perfluorooctanesulfonic acid anion, a pentafluorobenzenesulfonic acid anion, or a 3,5-bis(trifluoromethyl)benzenesulfonic acid anion.

The acid generator is preferably a compound capable of generating an acid represented by the following General Formula (IIIB) or (IVB) upon irradiation with actinic ray or radiation. Since the compound is a compound capable of generating an acid represented by the following General Formula (IIIB) or (IVB), a cyclic organic group is contained, and thus, resolution and roughness performance can be further improved.

As the non-nucleophilic anion, an anion capable of generating an organic acid represented by the following General Formula (IIIB) or (IVB) can be used.

In the general formulae,

Xf's each independently represent a fluorine atom or an alkyl group substituted with at least one fluorine atom,

R₁ and R₂ each independently represent a hydrogen atom or an alkyl group,

L's each independently represent a divalent linking group,

Cy represents a cyclic organic group,

Rf represents a group including a fluorine atom,

x represents an integer of 1 to 20,

y represents an integer of 0 to 10, and

z represents an integer of 0 to 10.

Xf represents a fluorine atom or an alkyl group substituted with at least one fluorine atom. The number of carbon atoms of the alkyl group is preferably 1 to 10, and more preferably 1 to 4. Further, the alkyl group substituted with at least one fluorine atom is preferably a perfluoroalkyl group.

Xf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms. Xf is more preferably a fluorine atom or CF₃. It is particularly preferable that both Xf's are fluorine atoms.

R₁ and R₂ each independently represent a hydrogen atom or an alkyl group.

The alkyl group of R₁ and R₂ may have a substituent, and is preferably an alkyl group having 1 to 4 carbon atoms. R₁ and R₂ are preferably a hydrogen atom.

L represents a divalent linking group. Examples of the divalent linking group include —COO—, —OCO—, —CONH—, —NHCO—, —CO—, —O—, —S—, —SO—, —SO₂—, an alkylene group (preferably having 1 to 6 carbon atoms), a cycloalkylene group (preferably having 3 to 10 carbon atoms), an alkenylene group (preferably having 2 to 6 carbon atoms), and a divalent linking group formed by combination of a plurality of these members. Among these, —COO—, —OCO—, —CONH—, —NHCO—, —CO—, —O—, —SO₂—, —COO-alkylene group-, —OCO-alkylene group-, —CONH-alkylene group-, or —NHCO-alkylene group- is preferable, and —COO—, —OCO—, —CONH—, —SO₂—, —COO-alkylene group-, or —OCO-alkylene group- is more preferable.

Cy represents a cyclic organic group. Examples of the cyclic organic group include an alicyclic group, an aryl group, and a heterocyclic group.

The alicyclic group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic group include a monocyclic cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic group include a polycyclic cycloalkyl group such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. Among these, an alicyclic group having a bulky structure with 7 or more carbon atoms, such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group, is preferable from the viewpoints of inhibiting the in-film diffusion in a post-exposure baking (PEB) step and improving the mask error enhancement factor (MEEF).

The aryl group may be monocyclic or polycyclic. Examples of the aryl group include a phenyl group, a naphthyl group, a phenanthryl group, and an anthryl group. Among these, a naphthyl group having a relatively low light absorbance at 193 nm is preferable.

The heterocyclic group may be monocyclic or polycyclic, but with a polycyclic heterocyclic group, the diffusion of an acid can further be inhibited. In addition, the heterocyclic group may have aromaticity or may not have aromaticity. Examples of the heterocycle having aromaticity include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. Examples of the heterocycle not having aromaticity include a tetrahydropyran ring, a lactone ring, a sultone ring, and a decahydroisoquinoline ring. The heterocycle in the heterocyclic group is particularly preferably a furan ring, a thiophene ring, a pyridine ring, or a decahydroisoquinoline ring. Examples of the lactone ring or sultone ring include lactone structures or sultone structures exemplified in the resin (P) as mentioned above.

The cyclic organic group as described above may have a substituent, and examples of the substituent include an alkyl group (may be linear or branched, preferably having 1 to 12 carbon atoms), a cycloalkyl group (may be monocyclic, polycyclic, or spirocyclic, preferably having 3 to 20 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), a hydroxyl group, an alkoxy group, an ester group, an amide group, a urethane group, a ureido group, a thioether group, a sulfonamide group, and a sulfonic ester group. Incidentally, the carbon constituting the cyclic organic group (the carbon contributing to ring formation) may be carbonyl carbon.

x is preferably 1 to 8, preferably 1 to 4, and particularly preferably 1. y is preferably 0 to 4, and more preferably 0. z is preferably 0 to 8, more preferably 0 to 4, and still more preferably 1.

Examples of the group containing a fluorine atom, represented by Rf, include an alkyl group having at least one fluorine atom, a cycloalkyl group having at least one fluorine atom, and an aryl group having at least one fluorine atom.

The alkyl group, a cycloalkyl group, and aryl group may be substituted with a fluorine atom or may be substituted with another substituent containing a fluorine atom. In the case where Rf is a cycloalkyl group having at least one fluorine atom or an aryl group having at least one fluorine atom, examples of other such substituents containing a fluorine atom include an alkyl group substituted with at least one fluorine atom.

Moreover, the alkyl group, a cycloalkyl group, and aryl group may further be substituted with a fluorine atom-free substituent. Examples of this substituent include ones not containing a fluorine atom out of those described above for Cy.

Examples of the alkyl group having at least one fluorine atom, represented by Rf, are the same as ones described above as the alkyl group substituted with at least one fluorine atom represented by Xf. Examples of the cycloalkyl group having at least one fluorine atom, represented by Rf, include a perfluorocyclopentyl group and a perfluorocyclohexyl group. Examples of the aryl group having at least one fluorine atom represented by Rf include a perfluorophenyl group.

In the general formulae, a particularly preferred aspect is an aspect in which x is 1, two Xf s are fluorine atoms, y is 0 to 4, both of R₁ and R₂ are hydrogen atoms, and z is 1. In such an aspect, the group has a small number of fluorine atoms and is hard to be distributed unevenly on the surface during formation of a resist film, and thus, is easily dispersed in the resist film.

Examples of the organic group represented by R₂₀₁, R₂₀₂, and R₂₀₃ include corresponding groups in the compounds (ZI-1), (ZI-2), (ZI-3), and (ZI-4) which will be described later.

Incidentally, the compound may be a compound having a plurality of structures represented by General Formula (ZI). For example, the compound may be a compound having a structure in which at least one of R₂₀₁ to R₂₀₃ in a compound represented by General Formula (ZI) is bonded to at least one of R₂₀₁ to R₂₀₃ in another compound represented by General Formula (ZI) through a single bond or a linking group.

More preferred examples of the components (ZI) include the compounds (ZI-1), (ZI-2), (ZI-3), and (ZI-4) which will be described below.

First, the compound (ZI-1) will be described.

The compound (ZI-1) is an arylsulfonium compound in which at least one of R₂₀₁ to R₂₀₃ in General Formula (ZI) is an aryl group, that is, a compound having arylsulfonium as the cation.

In the arylsulfonium compound, all of R₂₀₁ to R₂₀₃ may be an aryl group, or a part of R₂₀₁ to R₂₀₃ may be an aryl group, with the remainder being an alkyl group or a cycloalkyl group.

Examples of the arylsulfonium compound include a triarylsulfonium compound, a diarylalkylsulfonium compound, an aryldialkylsulfonium compound, a diarylcycloalkylsulfonium compound, and an aryldicycloalkylsulfonium compound.

The aryl group in the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure containing an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the heterocyclic structure include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue, and a benzothiophene residue. In the case where the arylsulfonium compound has two or more aryl groups, these two or more aryl groups may be the same as or different from each other.

The alkyl group or the cycloalkyl group which may be contained, if desired, in the arylsulfonium compound, is preferably a linear or branched alkyl group having 1 to 15 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

The aryl group, the alkyl group, and the cycloalkyl group of R₂₀₁ to R₂₀₃ may have, as the substituent, an alkyl group (for example, having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3 to 15 carbon atoms), an aryl group (for example, having 6 to 14 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group.

Next, the compound (ZI-2) will be described.

The compound (ZI-2) is a compound in which R₂₀₁ to R₂₀₃ in Formula (ZI) each independently represent an organic group not having an aromatic ring. The aromatic ring as used herein encompasses an aromatic ring containing a hetero atom.

The organic group not having an aromatic ring as R₂₀₁ to R₂₀₃ has generally 1 to 30 carbon atoms, and preferably 1 to 20 carbon atoms.

R₂₀₁ to R₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycarbonylmethyl group, and particularly preferably a linear or branched 2-oxoalkyl group.

Preferred examples of the alkyl group and the cycloalkyl group of R₂₀₁ to R₂₀₃ include a linear or branched alkyl group having 1 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group), and a cycloalkyl group having 3 to 10 carbon atoms (a cyclopentyl group, a cyclohexyl group, and a norbornyl group).

R₂₀₁ to R₂₀₃ may further be substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, and a nitro group.

Next, the compound (ZI-3) will be described.

The compound (ZI-3) is a compound represented by the following General Formula (ZI-3), having a phenacylsulfonium salt structure.

In General Formula (ZI-3),

R_(1c) to R_(5c) each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group, or an arylthio group,

R_(6c) and R_(7c) each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group, or an aryl group, and

R_(x) and R_(y) each independently represent an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.

Any two or more members out of R_(1c) to R_(5c), R_(5c) and R_(6c), R_(6c) and R_(7c), R_(5c) and R_(x), or R_(x) and R_(y) may be respectively bonded to each other to form a ring structure, and this ring structure may contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond.

Examples of the ring structure include an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aromatic heterocycle, and a polycyclic fused ring formed by combination of two or more members out of these rings. Examples of the ring structure include 3- to 10-membered rings, with 4- to 8-membered rings being preferable, and 5- or 6-membered rings being more preferable.

Examples of the group formed by combination of any two or more members out of R_(1c) to R_(5c), a pair of R_(6c) and R_(7c), or a pair of R_(x) and R_(y) include a butylene group, and a pentylene group.

The group formed by combination of a pair of R_(5c) and R_(6c), or a pair of R_(5c) and R_(x) is preferably a single bond or an alkylene group, and examples of the alkylene group include a methylene group and an ethylene group.

Z_(c) ⁻ represents a non-nucleophilic anion, and examples thereof include the same ones as the non-nucleophilic anions of Z⁻ in General Formula (ZI).

Specific examples of the alkoxy group in the alkoxycarbonyl group as R_(1c) to R_(5c) are the same as the specific examples of the alkoxy group as R_(1c) to R_(5c) above.

Specific examples of the alkyl group in the alkylcarbonyloxy group and the alkylthio group as R_(1c) to R_(5c) are the same as the specific examples of the alkyl group as R_(1c) to R₅ above.

Specific examples of the cycloalkyl group in the cycloalkylcarbonyloxy group as R_(1c) to R_(5c) are the same as the specific examples of the cycloalkyl group as R_(1c) to R_(5c) above.

Specific examples of the aryl group in the aryloxy group and the arylthio group as R_(1c) to R_(5c) are the same as the specific examples of the aryl group as R_(1c) to R_(5c) above.

Examples of the cation in the compound (ZI-2) or (ZI-3) in the present invention include the cations described after paragraph “0036” in the specification of US2012/0076996A.

Next, the compound (ZI-4) will be described.

The compound (ZI-4) is represented by the following General Formula (ZI-4).

In General Formula (ZI-4),

R₁₃ represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, or a group having a cycloalkyl group, and these groups may have a substituent,

R₁₄'s, in the case where they are present in plural numbers, each independently represent a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a group having a cycloalkyl group, and these groups may have a substituent,

R₁₅'s each independently represent an alkyl group, a cycloalkyl group, or a naphthyl group, these groups may have a substituent, two R₁₅'s may be bonded to each other to form a ring, and when two R₁₅'s are bonded to each other to form a ring, the ring skeleton may contain a hetero atom such as an oxygen atom and a nitrogen atom; and in an aspect, two R₁₅'s are alkylene groups, and are preferably bonded to each other to form a ring structure,

l represents an integer of 0 to 2;

r represents an integer of 0 to 8; and

Z⁻ represents a non-nucleophilic anion, and examples thereof include the same ones as the nucleophilic anions of Z⁻ in General Formula (ZI).

In General Formula (ZI-4), the alkyl groups of R₁₃, R₁₄, and R₁₅ are linear or branched, and preferably have 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-butyl group, and a t-butyl group.

Examples of the cation represented by General Formula (ZI-4) in the present invention include the cations described in paragraphs “0121”, “0123”, and “0124” of JP2010-256842A, paragraphs “0127”, “0129”, and “0130” of JP2011-76056A, and the like.

Next, General Formulae (ZII) and (ZIII) will be described.

In General Formulae (ZII) and (ZIII), R₂₀₄ to R₂₀₇ each independently represent an aryl group, an alkyl group, or a cycloalkyl group.

The aryl group of R₂₀₄ to R₂₀₇ is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group of R₂₀₄ to R₂₀₇ may be an aryl group having a heterocyclic structure containing an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the framework of the aryl group having a heterocyclic structure include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.

The alkyl group and the cycloalkyl group with respect to R₂₀₄ to R₂₀₇ are preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group) and a cycloalkyl group having 3 to 10 carbon atoms (for example, a cyclopentyl group, a cyclohexyl group, and a norbornyl group).

The aryl group, the alkyl group, and the cycloalkyl group of R₂₀₄ to R₂₀₇ may have a substituent, and examples of the substituent which the aryl group, an alkyl group and cycloalkyl group of R₂₀₄ to R₂₀₇ may have include an alkyl group (for example, having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3 to 15 carbon atoms), an aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.

Z⁻ represents a non-nucleophilic anion, and examples thereof include the same ones as the non-nucleophilic anions of Z⁻ in General Formula (ZI).

Other examples of the acid generator include compounds represented by the following General Formulae (ZIV), (ZV), and (ZVI).

In General Formulae (ZIV) to (ZVI),

Ar_(a) and Ar₄ each independently represent an aryl group,

R₂₀₈, R₂₀₉, and R₂₁₀ each independently represent an alkyl group, a cycloalkyl group, or an aryl group, and

A represents an alkylene group, an alkenylene group, or an arylene group.

Specific examples of the aryl group of Ar_(a), Ar₄, R₂₀₈, R₂₀₉, and R₂₁₀ include the same ones as the specific examples of the aryl group of R₂₀₁, R₂₀₂, and R₂₀₃ in General Formula (ZI-1).

Specific examples of the alkyl group and the cycloalkyl group of R₂₀₈, R₂₀₉, and R₂₁₀ include the same ones as the specific examples of the alkyl group and the cycloalkyl group of R₂₀₁, R₂₀₂, and R₂₀₃ in General Formula (ZI-2).

Examples of the alkylene group of A include alkylene having 1 to 12 carbon atoms (for example, a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, and an isobutylene group); examples of the alkenylene group of A include an alkenylene group having 2 to 12 carbon atoms (for example, an ethenylene group, a propenylene group, and a butenylene group); and examples of the arylene group of A include an arylene group having 6 to 10 carbon atoms (for example, a phenylene group, a tolylene group, and a naphthylene group).

Among the acid generators, particularly preferred examples thereof include the compounds exemplified in “0143” of US2012/0207978A1.

The acid generator can be synthesized by a known method, and can be synthesized in accordance with, for example, the method described in JP2007-161707A.

The acid generators may be used alone or in combination of two or more kinds thereof.

The content (the total content in the case where the compounds (B) are present in plural numbers) of the compound (B) in the composition is preferably 0.1% by mass to 30% by mass, more preferably 0.5% by mass to 25% by mass, still more preferably 3% by mass to 20% by mass, and particularly preferably 3% by mass to 15% by mass, with respect to the total solid content of the composition.

Incidentally, in the case where the acid generator is represented by General Formula (ZI-3) or (ZI-4), the content thereof (the total content in the case where the acid generators are present in plural numbers) is preferably 5% by mass to 35% by mass, more preferably 8% by mass to 30% by mass, still more preferably 9% by mass to 30% by mass, and particularly preferably 9% by mass to 25% by mass, with respect to the total solid content of the composition.

Specific examples of the acid generator are shown below, but the present invention is not limited thereto.

[3] Hydrophobic Resin

The composition of the present invention may contain a hydrophobic resin (hereinafter also referred to as a “hydrophobic resin (D)” or simply a “resin (D)”). Further, it is preferable that the hydrophobic resin (D) is different from the resin (P).

Although the hydrophobic resin (D) is preferably designed to be distributed unevenly on an interface as described above, it does not necessarily have to have a hydrophilic group in its molecule as different from the surfactant, and does not need to contribute to uniform mixing of polar/nonpolar materials.

Examples of the effect of addition of the hydrophobic resin include control of the static/dynamic contact angle of the resist film surface with respect to water, improvement of the immersion liquid tracking properties, and inhibition of outgassing.

The hydrophobic resin (D) preferably has one or more types of any of a “fluorine atom”, a “silicon atom”, and a “CH₃ partial structure which is contained in a side chain portion of a resin” from the point of view of uneven distribution on the film surface layer, and more preferably has two or more types.

In the case where hydrophobic resin (D) contains a fluorine atom and/or a silicon atom, the fluorine atom and/or the silicon atom in the hydrophobic resin (D) may be contained in the main chain or the side chain of the resin.

In the case where the hydrophobic resin (D) contains a fluorine atom, the resin is preferably a resin which contains an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom, as a partial structure having a fluorine atom.

The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, and more preferably having 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have a substituent other than a fluorine atom.

The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have a substituent other than a fluorine atom.

The aryl group having a fluorine atom is an aryl group such as a phenyl group and a naphthyl group, in which at least one hydrogen atom is substituted with a fluorine atom, and may further have a substituent other than a fluorine atom.

Preferred examples of the alkyl group having a fluorine atom, the cycloalkyl group having a fluorine atom, and the aryl group having a fluorine atom include groups represented by the following General Formulae (F2) to (F4), but the present invention is not limited thereto.

In General Formulae (F2) to (F4),

R₅₇ to R₆₈ each independently represent a hydrogen atom, a fluorine atom, or an (linear or branched) alkyl group, provided that at least one of R₅₇ to R₆₁, at least one of R₆₂ to R₆₄, and at least one of R₆₅ to R₆₈ each independently represent a fluorine atom or an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom.

It is preferable that R₅₇ to R₆₁, and R₆₅ to R₆₇ are all fluorine atoms. R₆₂, R₆₃, and R₆₈ are each preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and more preferably a perfluoroalkyl group having 1 to 4 carbon atoms. R₆₂ and R₆₃ may be linked to each other to form a ring.

Specific examples of the group represented by General Formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di(trifluoromethyl)phenyl group.

Specific examples of the group represented by General Formula (F3) include those exemplified in “0500” of US2012/0251948A1.

Specific examples of the group represented by General Formula (F4) include —C(CF₃)₂OH, —C(C₂F₅)₂OH, —C(CF₃)(CH₃)OH, and —CH(CF₃)OH, with —C(CF₃)₂OH being preferable.

The partial structure having a fluorine atom may be bonded directly to the main chain or may be bonded to the main chain through a group selected from the group consisting of an alkylene group, a phenylene group, an ether bond, a thioether bond, a carbonyl group, an ester bond, an amide bond, a urethane bond, and a ureylene bond, or a group formed by combination of two or more thereof.

The hydrophobic resin (D) may contain a silicon atom. As a partial structure having a silicon atom, a resin having an alkylsilyl structure (preferably a trialkylsilyl group), or a cyclic siloxane structure is preferable.

Specific examples of the alkylsilyl structure or the cyclic siloxane structure include a group represented by the following General Formulae (CS-1) to (CS-3).

In General Formulae (CS-1) to (CS-3),

R₁₂ to R₂₆ each independently represent a linear or branched alkyl group (preferably 1 to 20 carbon atoms) or a cycloalkyl group (preferably 3 to 20 carbon atoms).

L₃ to L₅ represent a single bond or a divalent linking group. Examples of a divalent linking group include one, or a combination (the total number of carbon atoms is preferably 12 or less) of two or more, which are selected from a group formed of an alkylene group, a phenylene group, an ether bond, a thioether bond, a carbonyl group, an ester bond, an amide bond, a urethane bond, and a urea bond.

n represents an integer of 1 to 5. n is preferably an integer of 2 to 4.

Examples of the repeating unit having a fluorine atom or a silicon atom include those exemplified in “0519” of US2012/0251948A1.

Furthermore, it is also preferable that the hydrophobic resin (D) includes a CH₃ partial structure in the side chain portion as described above.

Here, the CH₃ partial structure contained in the side chain portion in the hydrophobic resin (D) (hereinafter also simply referred to as a “side chain CH₃ partial structure”) is intended to include CH₃ partial structures contained in an ethyl group, a propyl group, and the like.

On the other hand, a methyl group bonded directly to the main chain of the hydrophobic resin (D) (for example, an α-methyl group in a repeating unit having a methacrylic acid structure) makes only a small contribution of uneven distribution to the surface of the hydrophobic resin (D) due to the effect of the main chain, and it is therefore not included in the CH₃ partial structure in the present invention.

More specifically, in the case where the hydrophobic resin (D) includes a repeating unit derived from a monomer having a polymerizable moiety with a carbon-carbon double bond, such as a repeating unit represented by the following General Formula (M), and in addition, R₁₁ to R₁₄ are CH₃ “themselves”, such CH₃ is not included in the CH₃ partial structure contained in the side chain portion in the present invention.

On the other hand, a CH₃ partial structure which is present through some atom(s) from the C—C main chain is intended to correspond to the CH₃ partial structure in the present invention. For example, in the case where R₁₁ is an ethyl group (CH₂CH₃), it is intended that the repeating unit has “one” CH₃ partial structure in the present invention.

In General Formula (M),

R₁₁ to R₁₄ each independently represent a side chain portion.

Examples of R₁₁ to R₁₄ at the side chain portion include a hydrogen atom and a monovalent organic group.

Examples of the monovalent organic group for R₁₁ to R₁₄ include an alkyl group, a cycloalkyl group, an aryl group, an alkyloxycarbonyl group, a cycloalkyloxycarbonyl group, an aryloxycarbonyl group, an alkylaminocarbonyl group, a cycloalkylaminocarbonyl group, and an arylaminocarbonyl group, each of which may further have a substituent.

It is preferable that the hydrophobic resin (D) is a resin including a repeating unit having the CH₃ partial structure in the side chain portion thereof. Further, it is more preferable that the hydrophobic resin has at least one repeating unit (x) of a repeating unit represented by the following General Formula (II) or a repeating unit represented by the following General Formula (III) as the repeating unit.

Hereinafter, the repeating unit represented by General Formula (II) will be described in detail.

In General Formula (II), X_(b1) represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom, and R₂ represents an organic group which has one or more CH₃ partial structures and is stable against an acid. Here, more specifically, the organic group which is stable against an acid is preferably an organic group which does not have “the acid-decomposable group” as described in the resin (P).

The alkyl group of X_(b1) is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a trifluoromethyl group, with the methyl group being preferable.

X_(b1) is preferably a hydrogen atom or a methyl group.

Examples of R₂ include an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group, and an aralkyl group, each of which has one or more CH₃ partial structures. Each of the cycloalkyl group, the alkenyl group, the cycloalkenyl group, the aryl group and the aralkyl group may further have an alkyl group as a substituent.

R₂ is preferably an alkyl group or an alkyl-substituted cycloalkyl group, each of which has one or more CH₃ partial structures.

The number of the CH₃ partial structures contained in the organic group which has one or more CH₃ partial structures and is stable against an acid as R₂ is preferably 2 to 10, and more preferably 2 to 8.

Specific preferred examples of the repeating unit represented by General Formula (II) are shown below, but the present invention is not limited thereto.

The repeating unit represented by General Formula (II) is preferably a repeating unit which is stable against an acid (acid-indecomposable), and specifically, it is preferably a repeating unit having no group capable of decomposing by the action of an acid to generate a polar group.

Hereinafter, the repeating unit represented by General Formula (III) will be described in detail.

In General Formula (III), X_(b2) represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom, R₃ represents an organic group which has one or more CH₃ partial structures and is stable against an acid, and n represents an integer of 1 to 5.

The alkyl group of X_(b2) is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a trifluoromethyl group, but a hydrogen atom is preferable.

X_(b2) is preferably a hydrogen atom.

R₃ is an organic group which is stable against an acid, and therefore, more specifically, R₃ is preferably an organic group which does not have “the acid-decomposable group” as described in the resin (P).

Examples of R₃ include an alkyl group having one or more CH₃ partial structures.

The number of the CH₃ partial structures contained in the organic group which has one or more CH₃ partial structures and is stable against an acid as R₃ is preferably 1 to 10, more preferably 1 to 8, and still more preferably 1 to 4.

n represents an integer of 1 to 5, more preferably 1 to 3, and still more preferably 1 or 2.

Specific preferred examples of the repeating unit represented by General Formula (III) are shown below, but the present invention is not limited thereto.

The repeating unit represented by General Formula (III) is preferably a repeating unit which is stable against an acid (acid-indecomposable), and specifically, it is preferably a repeating unit which has no group capable of decomposing by the action of an acid to generate a polar group.

In the case where the hydrophobic resin (D) contains a CH₃ partial structure in the side chain portion thereof, and in particular, it has neither a fluorine atom nor a silicon atom, the content of at least one repeating unit (x) of the repeating unit represented by General Formula (II) or the repeating unit represented by General Formula (III) is preferably 90% by mole or more, and more preferably 95% by mole or more, with respect to all the repeating units of the hydrophobic resin (D). Further, the content is usually 100% by mole or less with respect to all the repeating units of the hydrophobic resin (D).

By incorporating at least one repeating unit (x) of the repeating unit represented by General Formula (II) or the repeating unit represented by General Formula (III) in a proportion of 90% by mole or more with respect to all the repeating units of the hydrophobic resin (D) into the hydrophobic resin (D), the surface free energy of the hydrophobic resin (D) is increased. As a result, it is difficult for the hydrophobic resin (D) to be unevenly distributed on the surface of the resist film and the static/dynamic contact angle of the resist film with respect to water can be securely increased, thereby enhancing the immersion liquid tracking properties.

In addition, the hydrophobic resin (D) may have at least one group selected from the following groups (x) to (z) in the case (i) of containing a fluorine atom and/or a silicon atom as well as in the case (ii) of containing a CH₃ partial structure in the side chain portion:

(x) an acid group,

(y) a group having a lactone structure, an acid anhydride group, or an acid imide group, and

(z) a group capable of decomposing by the action of an acid.

Examples of the acid group (x) include a phenolic hydroxyl group, a carboxylic acid group, a fluorinated alcohol group, a sulfonic acid group, a sulfonamide group, a sulfonylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group, a bis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imide group, a tris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylene group.

Preferred examples of the acid group include a fluorinated alcohol group (preferably hexafluoroisopropanol), a sulfonimide group, and a bis(alkylcarbonyl)methylene group.

Examples of the repeating unit having an acid group (x) include a repeating unit in which the acid group is directly bonded to the main chain of the resin, such as a repeating unit by an acrylic acid or a methacrylic acid, and a repeating unit in which the acid group is bonded to the main chain of the resin through a linking group, and the acid group may also be introduced into the polymer chain terminal by using a polymerization initiator or chain transfer agent containing an acid group during the polymerization. All of these cases are preferable. The repeating unit having an acid group (x) may have at least one of a fluorine atom or a silicon atom.

The content of the repeating units having an acid group (x) is preferably 1% by mole to 50% by mole, more preferably 3% by mole to 35% by mole, and still more preferably 5% by mole to 20% by mole, with respect to all the repeating units in the hydrophobic resin (D).

Specific examples of the repeating unit having an acid group (x) are shown below, but the present invention is not limited thereto. In the formulae, Rx represents a hydrogen atom, CH₃, CF₃, or, CH₂OH.

As the group having a lactone structure, the acid anhydride group, or the acid imide group (y), the group having a lactone structure is particularly preferable.

The repeating unit including such a group is, for example, a repeating unit in which the group is directly bonded to the main chain of the resin, such as a repeating unit by an acrylic ester or a methacrylic ester. This repeating unit may be a repeating unit in which the group is bonded to the main chain of the resin through a linking group. Alternatively, this repeating unit may be introduced into the terminal of the resin by using a polymerization initiator or chain transfer agent having the group during the polymerization.

Examples of the repeating unit having a group having a lactone structure include the same ones as those of the repeating unit having a lactone structure as described earlier in the section of the resin (P).

The content of the repeating units having a group having a lactone structure, an acid anhydride group, or an acid imide group is preferably 1% by mole to 100% by mole, more preferably 3% by mole to 98% by mole, and still more preferably 5% by mole to 95% by mole, with respect to all the repeating units in the hydrophobic resin (D).

In the hydrophobic resin (D), examples of the repeating unit having a group (z) capable of decomposing by the action of an acid include the same ones as the repeating units containing an acid-decomposable group, as mentioned with respect to the resin (P). The repeating unit having a group (z) capable of decomposing by the action of an acid may contain at least one of a fluorine atom or a silicon atom. In the hydrophobic resin (D), the content of the repeating units having a group (z) capable of decomposing by the action of an acid is preferably 1% by mole to 80% by mole, more preferably 10% by mole to 80% by mole, and still more preferably 20% by mole to 60% by mole, with respect to all the repeating units in the resin (D).

The hydrophobic resin (D) may further have a repeating unit represented by the following General Formula (III).

In General Formula (III),

R_(c31) represents a hydrogen atom, an alkyl group (which may be substituted with a fluorine atom or the like), a cyano group, or a —CH₂—O—R_(ac2) group, in which Rac₂ represents a hydrogen atom, an alkyl group, or an acyl group, and R_(c31) is preferably a hydrogen atom, a methyl group, a hydroxymethyl group, or a trifluoromethyl group, and particularly preferably a hydrogen atom or a methyl group,

R_(c32) represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, or an aryl group, each of which may be substituted with a group containing a fluorine atom or a silicon atom, and

L_(c3) represents a single bond or a divalent linking group.

In General Formula (III), the alkyl group of R_(c32) is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.

The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.

The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.

The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.

The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and more preferably a phenyl group or a naphthyl group, and these groups may have a substituent.

R_(c32) is preferably an unsubstituted alkyl group or an alkyl group substituted with a fluorine atom.

The divalent linking group of L_(c3) is preferably an alkylene group (preferably having 1 to 5 carbon atoms), an ether bond, a phenylene group, or an ester bond (a group represented by —COO—).

The content of the repeating units represented by General Formula (III) is preferably 1% by mole to 100% by mole, more preferably 10% by mole to 90% by mole, and still more preferably 30% by mole to 70% by mole, with respect to all the repeating units in the hydrophobic resin (D).

It is also preferable that the hydrophobic resin (D) further has a repeating unit represented by the following General Formula (CII-AB).

In Formula (CII-AB),

R_(c11)′ and R_(c12)′ each independently represent a hydrogen atom, a cyano group, a halogen atom, or an alkyl group, and

Zc′ represents an atomic group for forming an alicyclic structure containing two carbon atoms (C—C) to which Zc′ is bonded.

The content of the repeating units represented by General Formula (CII-AB) is preferably 1% by mole to 100% by mole, more preferably 10% by mole to 90% by mole, and still more preferably 30% by mole to 70% by mole, with respect to all the repeating units in the hydrophobic resin (D).

Specific examples of the repeating units represented by General Formulae (III) and (CII-AB) are shown above, but the present invention is not limited thereto. In the formulae, Ra represents H, CH₃, CH₂OH, CF₃, or CN.

In the case where the hydrophobic resin (D) has a fluorine atom, the content of the fluorine atom is preferably 5% by mass to 80% by mass, and more preferably 10% by mass to 80% by mass, with respect to the weight-average molecular weight of the hydrophobic resin (D). Further, the proportion of the repeating units containing a fluorine atom is preferably 10% by mole to 100% by mole, and more preferably 30% by mole to 100% by mole, with respect to all the repeating units included in the hydrophobic resin (D).

In the case where the hydrophobic resin (D) has a silicon atom, the content of the silicon atom is preferably 2% by mass to 50% by mass, and more preferably 2% by mass to 30% by mass, with respect to the weight-average molecular weight of the hydrophobic resin (D). Further, the proportion of the repeating unit containing a silicon atom is preferably 10% by mole to 100% by mole, and more preferably 20% by mole to 100% by mole, with respect to all the repeating units included in the hydrophobic resin (D).

On the other hand, in particular, in the case where the hydrophobic resin (D) contains a CH₃ partial structure in the side chain portion thereof, it is also preferable that the hydrophobic resin (D) has a form having substantially neither a fluorine atom nor a silicon atom. In this case, specifically the content of the repeating units containing a fluorine atom or a silicon atom is preferably 5% by mole or less, more preferably 3% by mole or less, still more preferably 1% by mole or less, and ideally 0% by mole, that is, containing neither a fluorine atom nor a silicon atom, with respect to all the repeating units in the hydrophobic resin (D). In addition, it is preferable that the hydrophobic resin (D) is composed substantially of a repeating unit constituted with only an atom selected from the group consisting of a carbon atom, an oxygen atom, a hydrogen atom, a nitrogen atom, and a sulfur atom. More specifically, the proportion of the repeating unit constituted with only an atom selected from the group consisting of a carbon atom, an oxygen atom, a hydrogen atom, a nitrogen atom, and a sulfur atom is preferably 95% by mole or more, more preferably 97% by mole or more, still more preferably 99% by mole or more, and ideally 100% by mole, of all the repeating units in the hydrophobic resin (D).

The weight-average molecular weight of the hydrophobic resin (D) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and still more preferably 2,000 to 15,000.

Furthermore, the hydrophobic resins (D) may be used alone or in combination of two or more kinds thereof.

The content of the hydrophobic resins (D) in the composition is preferably 0.01% by mass to 10% by mass, more preferably 0.05% by mass to 8% by mass, and still more preferably 0.1% by mass to 7% by mass, with respect to the total solid content of the composition of the present invention.

In the hydrophobic resin (D), it is certain that the content of impurities such as metal is small, but the content of residual monomers or oligomer components is also preferably 0.01% by mass to 5% by mass, more preferably 0.01% by mass to 3% by mass, and still more preferably 0.05% by mass to 1% by mass. Within these ranges, a composition free from a change in-liquid extraneous materials or in sensitivity over time, or the like can be obtained. Further, from the viewpoints of a resolution, a resist profile, the side wall of a resist pattern, a roughness, and the like, the molecular weight distribution (Mw/Mn, also referred to as a dispersity) is preferably in the range of 1 to 5, more preferably in the range of 1 to 3, and still more preferably in the range of 1 to 2.

As the hydrophobic resin (D), various commercial products may be used, or the hydrophobic resin (D) may be synthesized by an ordinary method (for example, radical polymerization). Examples of the general synthesis method include a batch polymerization method of dissolving monomer species and an initiator in a solvent and heating the solution, thereby carrying out the polymerization, and a dropping polymerization method of adding dropwise a solution containing monomer species and an initiator to a heated solvent for 1 hour to 10 hours, with the dropping polymerization method being preferable.

The reaction solvent, the polymerization initiator, the reaction conditions (a temperature, a concentration, and the like) and the method for purification after reaction are the same as ones described for the resin (P), but in the synthesis of the hydrophobic resin (D), the concentration at the reactant is preferably 30% by mass to 50% by mass.

Specific examples of the hydrophobic resin (D) are shown below. Further, the molar ratio of the repeating units (corresponding to the respective repeating units in order from the left side), the weight-average molecular weight, and the dispersity with respect to the respective resins are shown in the following tables.

TABLE 1 Resin Compositional ratio Molecular weight Dispersity B-1 50/50 4800 1.4 B-2 50/50 5100 2.1 B-3 40/60 6600 1.8 B-4 100 5500 1.7 B-5 45/55 4400 1.6 B-6 50/50 6000 1.5 B-7 40/10/50 6200 1.6 B-8 50/50 5800 1.5 B-9 80/20 4800 1.8 B-10 50/20/30 4900 1.9 B-11 50/10/40 5300 2.0 B-12 40/20/40 5500 1.4 B-13 60/40 5900 1.3 B-14 50/50 6200 1.5 B-15 40/15/45 6100 1.8 B-16 57/39/2/2 6000 1.6 B-17 45/20/35 6600 1.6 B-18 40/30/30 5500 1.7 B-19 100 4900 1.6 B-20 100 4400 1.8 B-21 60/40 4500 1.9 B-22 55/45 6200 1.3 B-23 100 5700 1.5 B-24 100 5800 2.0 B-25 100 6000 1.5 B-26 100 6000 1.6 B-27 100 6200 1.8 B-28 50/50 6500 1.7 B-29 90/8/2 6500 1.5 B-30 90/10 6900 1.7 B-31 95/5  4900 1.8 B-32 80/20 5200 1.9 B-33 75/15/10 5900 1.6 B-34 75/25 6000 1.5 B-35 80/20 5700 1.4 B-36 100 5300 1.7 B-37 20/80 5400 1.6 B-38 50/50 4800 1.6 B-39 70/30 4500 1.6 B-40 100 5500 1.5 B-41 40/40/20 5800 1.5 B-42 35/35/30 6200 1.4

TABLE 2 Resin Composition Mw Mw/Mn C-1 50/50 9600 1.74 C-2 60/40 34500 1.43 C-3 30/70 19300 1.69 C-4 90/10 26400 1.41 C-5 100 27600 1.87 C-6 80/20 4400 1.96 C-7 100 16300 1.83 C-8  5/95 24500 1.79 C-9 20/80 15400 1.68 C-10 50/50 23800 1.46 C-11 100 22400 1.57 C-12 10/90 21600 1.52 C-13 100 28400 1.58 C-14 50/50 16700 1.82 C-15 100 23400 1.73 C-16 60/40 18600 1.44 C-17 80/20 12300 1.78 C-18 40/60 18400 1.58 C-19 70/30 12400 1.49 C-20 50/50 23500 1.94 C-21 10/90 7600 1.75 C-22  5/95 14100 1.39 C-23 50/50 17900 1.61 C-24 10/90 24600 1.72 C-25 50/40/10 23500 1.65 C-26 60/30/10 13100 1.51 C-27 50/50 21200 1.84 C-28 10/90 19500 1.66

[4] Acid Diffusion Control Agent

The composition of the present invention preferably contains an acid diffusion control agent. The acid diffusion control agent acts as a quencher that inhibits a reaction of the acid-decomposable resin in the unexposed area by excessive generated acids by trapping the acids generated from an acid generator or the like upon exposure. As the acid diffusion control agent, a basic compound, a low-molecular-weight compound which has a nitrogen atom and a group capable of leaving by the action of an acid, a basic compound whose basicity is reduced or lost upon irradiation with actinic ray or radiation, or an onium salt which becomes a relatively weak acid with respect to an acid generator can be used.

Preferred examples of the basic compound include compounds having structures represented by the following Formulae (A) to (E).

In General Formulae (A) and (E),

R²⁰⁰, R²⁰¹, and R²⁰², which may be the same as or different from each other, represent a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms), or an aryl group (having 6 to 20 carbon atoms), and R²⁰¹ and R²⁰² may be bonded to each other to form a ring.

R²⁰³, R²⁰⁴, R²⁰⁵, and R²⁰⁶, which may be the same as or different from each other, each represent an alkyl group having 1 to 20 carbon atoms.

With regard to the alkyl group, the alkyl group having a substituent is preferably an aminoalkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, or a cyanoalkyl group having 1 to 20 carbon atoms.

It is more preferable that the alkyl groups in General Formulae (A) and (E) are unsubstituted.

Preferred examples of the compound include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, and piperidine. More preferred examples of the compound include a compound having an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, a trialkylamine structure, an aniline structure, or a pyridine structure; an alkylamine derivative having a hydroxyl group and/or an ether bond; and an aniline derivative having a hydroxyl group and/or an ether bond.

Specific preferred examples of the compound include the compounds exemplified in “0379” of US2012/0219913A1.

Preferred examples of the basic compound include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound containing a sulfonic ester group, and an ammonium salt compound having a sulfonic ester group.

As the amine compound, a primary, secondary, or tertiary amine compound can be used, and an amine compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. The amine compound is more preferably a tertiary amine compound. Any amine compound is available as long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, and a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 6 to 12 carbon atoms) may be bonded to the nitrogen atom, in addition to the alkyl group. The amine compound preferably has an oxygen atom in the alkyl chain to form an oxyalkylene group. The number of the oxyalkylene groups within the molecule is 1 or more, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH₂CH₂O—) or an oxypropylene group (—CH(CH₃)CH₂O— or —CH₂CH₂CH₂O—) is preferable, and an oxyethylene group is more preferable.

As the ammonium salt compound, a primary, secondary, tertiary, or quaternary ammonium salt compound can be used, and an ammonium salt compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. Any ammonium salt compound is available as long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, and a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 6 to 12 carbon atoms) may be bonded to the nitrogen atom, in addition to the alkyl group. The ammonium salt compound preferably has an oxygen atom in the alkyl chain to form an oxyalkylene group. The number of the oxyalkylene groups within the molecule is 1 or more, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH₂CH₂O—) or an oxypropylene group (—CH(CH₃)CH₂O— or —CH₂CH₂CH₂O—) is preferable, and an oxyethylene group is more preferable.

Examples of the anion of the ammonium salt compound include a halogen atom, sulfonate, borate, and phosphate, but among these, the halogen atom and sulfonate are preferable.

Furthermore, the following compounds are also preferable as a basic compound.

In addition to the compounds as described above, as the basic compound, the compounds described in “0180” to “0225” of JP2011-22560A, “0218” to “0219” of JP2012-137735A, and “0416” to “0438” of WO2011/158687A1, and the like can also be used.

These basic compounds may be used alone or in combination of two or more kinds thereof.

The composition of the present invention may or may not contain the basic compound, but in the case where it contains the basic compound, the content of the basic compound is usually 0.001% by mass to 10% by mass, and preferably 0.01% by mass to 5% by mass, with respect to the solid content of the composition.

The ratio between the acid generator (including the acid generator (A′)) and the basic compound to be used in the composition is preferably the acid generator/basic compound (molar ratio)=2.5 to 300. That is, the molar ratio is preferably 2.5 or more in view of sensitivity and resolving power, and is preferably 300 or less in view of suppressing the reduction in resolving power due to thickening of the resist pattern with aging after exposure until the heat treatment. The acid generator/basic compound (molar ratio) is more preferably 5.0 to 200, and still more preferably 7.0 to 150.

The low-molecular-weight compound (hereinafter also referred to as a “compound (C)”) which has a nitrogen atom and a group capable of leaving by the action of an acid is preferably an amine derivative having a group capable of leaving by the action of an acid on a nitrogen atom.

As the group capable of leaving by the action of an acid, an acetal group, a carbonate group, a carbamate group, a tertiary ester group, a tertiary hydroxyl group, or a hemiaminal ether group are preferable, and a carbamate group or a hemiaminal ether group is particularly preferable.

The molecular weight of the compound (C) is preferably 100 to 1,000, more preferably 100 to 700, and particularly preferably 100 to 500.

The compound (C) may have a carbamate group having a protecting group on a nitrogen atom. The protecting group constituting the carbamate group can be represented by the following General Formula (d-1).

In General Formula (d-1),

R_(b)'s each independently represent a hydrogen atom, an alkyl group (preferably having 1 to 10 carbon atoms), a cycloalkyl group (preferably having 3 to 30 carbon atoms), an aryl group (preferably having 3 to 30 carbon atoms), an aralkyl group (preferably having 1 to 10 carbon atoms), or an alkoxyalkyl group (preferably having 1 to 10 carbon atoms). R_(b)'s may be bonded to each other to form a ring.

The alkyl group, the cycloalkyl group, the aryl group, or the aralkyl group represented by R_(b) may be substituted with a functional group such as a hydroxyl group, a cyano group, an amino group, a pyrrolidino group, a piperidino group, a morpholino group, and an oxo group, an alkoxy group, or a halogen atom. This shall apply to the alkoxyalkyl group represented by R_(b).

R_(b) is preferably a linear or branched alkyl group, a cycloalkyl group, or an aryl group, and more preferably a linear or branched alkyl group, or a cycloalkyl group.

Examples of the ring formed by the mutual linking of two R_(b)'s include an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic hydrocarbon group, and derivatives thereof.

Examples of the specific structure of the group represented by General Formula (d-1) include, but are not limited to, structures disclosed in paragraph “0466” of US2012/0135348A1.

It is particularly preferable that the compound (C) has a structure represented by the following General Formula (6)

In General Formula (6), R_(a) represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group. When 1 is 2, two R_(a)'s may be the same as or different from each other. Two R_(a)'s may be linked to each other to form a heterocycle together with the nitrogen atom in the formula. The heterocycle may contain a hetero atom other than the nitrogen atom in the formula.

R_(b) has the same meaning as R_(b) in General Formula (d-1), and preferred examples are also the same.

l represents an integer of 0 to 2, and m represents an integer of 1 to 3, satisfying l+m=3.

In General Formula (6), the alkyl group, the cycloalkyl group, the aryl group, and the aralkyl group as R_(a) may be substituted with the same groups as the group mentioned above as a group which may be substituted in the alkyl group, the cycloalkyl group, the aryl group, and the aralkyl group as R_(b).

Specific examples of the alkyl group, the cycloalkyl group, the aryl group, and the aralkyl group (such the alkyl group, cycloalkyl group, aryl group, and aralkyl group may be substituted with the groups as described above) of R_(a) include the same groups as the specific of examples as described above with respect to R_(b).

Specific examples of the particularly preferred compound (C) in the present invention include, but are not limited to, the compounds disclosed in paragraph “0475” of US2012/0135348A1.

The compound represented by General Formula (6) can be synthesized in accordance with JP2007-298569A, JP2009-199021A, and the like.

In the present invention, the low-molecular-weight compound (C) having a group capable of leaving by the action of an acid on a nitrogen atom may be used alone or as a mixture of two or more kinds thereof.

The content of the compounds (C) in the composition of the present invention is preferably 0.001% by mass to 20% by mass, more preferably 0.001% by mass to 10% by mass, and still more preferably 0.01% by mass to 5% by mass, with respect to the total solid content of the composition.

The basic compound whose basicity is reduced or lost upon irradiation with actinic ray or radiation (hereinafter also referred to as a “compound (PA)”) is a compound which has a functional group with proton acceptor properties, and decomposes upon irradiation with actinic ray or radiation to exhibit deterioration in proton acceptor properties, no proton acceptor properties, or a change from the proton acceptor properties to acid properties.

The functional group with proton acceptor properties refers to a functional group having a group or an electron which is capable of electrostatically interacting with a proton, and for example, means a functional group with a macrocyclic structure, such as a cyclopolyether, or a functional group containing a nitrogen atom having an unshared electron pair not contributing to π-conjugation. The nitrogen atom having an unshared electron pair not contributing to π-conjugation is, for example, a nitrogen atom having a partial structure represented by the following formula.

Preferred examples of the partial structure of the functional group with proton acceptor properties include crown ether, azacrown ether, primary to tertiary amine, pyridine, imidazole, and pyrazine structures.

The compound (PA) decomposes upon irradiation with actinic ray or radiation to generate a compound exhibiting deterioration in proton acceptor properties, no proton acceptor properties, or a change from the proton acceptor properties to acid properties. Here, exhibiting deterioration in proton acceptor properties, no proton acceptor properties, or a change from the proton acceptor properties to acid properties means a change of proton acceptor properties due to the proton being added to the functional group with proton acceptor properties, and specifically a decrease in the equilibrium constant at chemical equilibrium when a proton adduct is generated from the compound (PA) having the functional group with proton acceptor properties and the proton.

The proton acceptor properties can be confirmed by carrying out pH measurement.

In the present invention, the acid dissociation constant pKa of the compound generated by the decomposition of the compound (PA) upon irradiation with actinic ray or radiation preferably satisfies pKa<−1, more preferably −13<pKa<−1, and still more preferably −13<pKa<−3.

In the present invention, the acid dissociation constant pKa indicates an acid dissociation constant pKa in an aqueous solution, and is described, for example, in Chemical Handbook (II) (Revised 4^(th) Edition, 1993, compiled by the Chemical Society of Japan, Maruzen Company, Ltd.), and a lower value thereof indicates higher acid strength. Specifically, the pKa in an aqueous solution may be measured by using an infinite-dilution aqueous solution and measuring the acid dissociation constant at 25° C., or a value based on the Hammett substituent constants and the database of publicly known literature data can also be obtained by computation using the following software package 1. All the values of pKa described in the present specification indicate values determined by computation using this software package.

Software package 1: Advanced Chemistry Development (ACD/Labs) Software V 8.14 for Solaris (1994-2007 ACD/Labs).

The compound (PA) generates a compound represented by the following General Formula (PA-1), for example, as the proton adduct generated by decomposition upon irradiation with actinic ray or radiation. The compound represented by General Formula (PA-1) is a compound exhibiting deterioration in proton acceptor properties, no proton acceptor properties, or a change from the proton acceptor properties to acid properties since the compound has a functional group with proton acceptor properties as well as an acidic group, as compared with the compound (PA). Q-A-(X)_(n)—B—R  (PA-1)

In General Formula (PA-1),

Q represents —SO₃H, —CO₂H, or —W₁NHW₂R_(f), in which R_(f) represents an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms), or an aryl group (preferably having 6 to 30 carbon atoms), and W₁ and W₂ each independently represent —SO₂— or —CO—,

A represents a single bond or a divalent connecting group,

X represents —SO₂— or —CO—,

n is 0 or 1,

B represents a single bond, an oxygen atom, or —N(R_(x))R_(y)—, in which R_(x) represents a hydrogen atom or a monovalent organic group, and R_(y) represents a single bond or a divalent organic group, provided that R_(x) may be bonded to R_(y) to form a ring or may be bonded to R to form a ring, and

R represents a monovalent organic group having a functional group with proton acceptor properties.

General Formula (PA-1) will be described in more detail.

The divalent linking group in A is preferably a divalent linking group having 2 to 12 carbon atoms, such as and examples thereof include an alkylene group and a phenylene group. The divalent linking group is more preferably an alkylene group having at least one fluorine atom, preferably having 2 to 6 carbon atoms, and more preferably having 2 to 4 carbon atoms. The alkylene chain may contain a linking group such as an oxygen atom and a sulfur atom. In particular, the alkylene group is preferably an alkylene group in which 30% to 100% by number of the hydrogen atoms are substituted with fluorine atoms is preferable, and more preferably, the carbon atom bonded to the Q site has a fluorine atom. The alkylene group is still more preferably a perfluoroalkylene group, and even still more preferably a perfluoroethylene group, a perfluoropropylene group, or a perfluorobutylene group.

The monovalent organic group in R_(x) is preferably an organic group having 1 to 30 carbon atoms, and examples thereof include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. These groups may further have a substituent.

The alkyl group in R_(x) may have a substituent, is preferably a linear and branched alkyl group having 1 to 20 carbon atoms, and may have an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain.

The cycloalkyl group in R_(x) may have a substituent, is preferably a monocyclic cycloalkyl or polycyclic cycloalkyl group having 3 to 20 carbon atoms, and may have an oxygen atom, a sulfur atom, or a nitrogen atom in the ring.

The aryl group in R_(x) may have a substituent, is preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group and a naphthyl group.

The aralkyl group in R_(x) may have a substituent, is preferably an aralkyl group having 7 to 20 carbon atoms, and examples thereof include a benzyl group and a phenethyl group.

The alkenyl group in R_(x) may have a substituent and may be linear, or branched. The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms. Examples of the alkenyl group include a vinyl group, an allyl group, and a styryl group.

Examples of a substituent in the case where R_(x) further has a substituent include a halogen atom, a linear, branched, or cyclic alkyl group, an alkenyl group, an alkanyl group, an aryl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a cyano group, a carboxyl group, a hydroxyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a heterocyclic oxy group, an acyloxy group, an amino group, a nitro group, a hydrazino group, and a heterocyclic group.

Preferred examples of the divalent organic group in R_(y) include an alkylene group.

Examples of the ring structure which may be formed by the mutual bonding of R_(x) and R_(y) include 5- to 10-membered rings, containing a nitrogen atom, and particularly preferably a 6-membered ring.

The functional group with proton acceptor properties in R is the same as above, and examples thereof include groups having a nitrogen-containing heterocyclic aromatic structure, such as azacrown ether, primary to tertiary amine, pyridine, and imidazole.

The organic group having such a structure is preferably an organic group having 4 to 30 carbon atoms, and examples thereof include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group.

The alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, or the alkenyl group in R is the same as the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, or the alkenyl group as mentioned as R_(x).

When B is —N(R_(x))R_(y)—, it is preferable that R and R_(x) are bonded to each other to form a ring. The formation of a ring structure improves the stability and enhances the storage stability of a composition using the same. The number of carbon atoms which form a ring is preferably 4 to 20, the ring may be monocyclic or polycyclic, and an oxygen atom, and a sulfur atom, or a nitrogen atom may be contained in the ring.

Examples of the monocyclic structure include a 4-membered ring, a 5-membered ring, a 6-membered ring, a 7-membered ring, and a 8-membered ring, each containing a nitrogen atom, or the like. Examples of the polycyclic structure include structures formed by a combination of two, or three or more monocyclic structures.

R_(f) of —W₁NHW₂R_(f) represented by Q is preferably an alkyl group having 1 to 6 carbon atoms, which may have a fluorine atom, and more preferably a perfluoroalkyl group having 1 to 6 carbon atoms. Further, it is preferable that at least one of W₁ or W₂ is —SO₂—, with a case where both W₁ and W₂ are —SO₂— being more preferable.

Q is particularly preferably —SO₃H or —CO₂H from the viewpoint of the hydrophilicity of an acid group.

The compound represented by General Formula (PA-1) in which Q moiety is sulfonic acid can be synthesized by a common sulfonamidation reaction. For example, the compound can be obtained by a method in which one sulfonyl halide moiety of a bissulfonyl halide compound is selectively reacted with an amine compound after forming a sulfonamide bond, and the another sulfonyl halide moiety thereof is hydrolyzed, or a method in which cyclic sulfonic acid anhydride is reacted with an amine compound to cause ring opening.

The compound (PA) is preferably an ionic compound. The functional group with proton acceptor properties may be contained in an anion moiety or a cation moiety, and it is preferable that the functional group is contained in an anion moiety.

Preferred examples of the compound (PA) include compounds represented by the following General Formulae (4) to (6). R_(f)—W₂—N⁻—W₁-A-(X)_(n)—B—R[C]⁺  (4) R—SO₃ ⁻[C]⁺  (5) R—CO₂ ⁻[C]⁺  (6)

In General Formulae (4) to (6), A, X, n, B, R, R_(f), W₁, and W₂ each have the same definitions as those in General Formula (PA-1).

C⁺ represents a counter cation.

The counter cation is preferably an onium cation. More specifically, preferred examples thereof include a sulfonium cation described as S⁺(R₂₀₁)(R₂₀₂)(R₂₀₃) in General Formula (ZI) and an iodonium cation described as I⁺(R₂₀₄)(R₂₀₅) in General Formula (ZII) with regard to the aforementioned acid generator.

Specific examples of the compound (PA) include the compounds exemplified in “0280” of US2011/0269072A1.

Furthermore, in the present invention, compounds (PA) other than the compound capable of generating the compound represented by General Formula (PA-1) can also be appropriately selected. For example, a compound which is an ionic compound and contains a proton acceptor moiety at its cation moiety may be used. More specific examples thereof include a compound represented by the following General Formula (7).

In the formula, A represents a sulfur atom or an iodine atom,

m represents 1 or 2 and n represents 1 or 2, provided that m+n=3 when A is a sulfur atom and that m+n=2 when A is an iodine atom,

R represents an aryl group,

R_(N) represents an aryl group substituted with the functional group with proton acceptor properties, and X⁻ represents a counter anion.

Specific examples of X⁻ include the same anions as those of the anion of the acid generator.

Specific preferred examples of the aryl group of R and R_(N) include a phenyl group.

Specific examples of the functional group with proton acceptor properties contained in R_(N) are the same as those of the functional group with proton acceptor properties in Formula (PA-1) above.

Specific examples of the ionic compounds having a proton acceptor site at a cationic moiety include the compounds exemplified in “0291” of US2011/0269072A1.

Furthermore, such compounds can be synthesized, for example, with reference to the methods described in JP2007-230913A, JP2009-122623A, and the like.

The compound (PA) may be used alone or in combination of two or more kinds thereof.

The content of the compound (PA) is preferably 0.1% by mass to 10% by mass, and more preferably 1% by mass to 8% by mass, with respect to the total solid content of the composition.

In the composition of the present invention, an onium salt which becomes a relatively weak acid with respect to the acid generator can be used as an acid diffusion control agent.

In the case of mixing the acid generator and an onium salt generating an acid which is a relatively weak acid with respect to the acid generated from the acid generator, and using the mixture, when the acid generated from the acid generator upon irradiation with actinic ray or radiation collides with an onium salt having an unreacted weak acid anion, a weak acid is discharged by salt exchange to generate an onium salt having a strong acid anion. In this process, the strong acid is exchanged with a weak acid having a lower catalytic ability, and therefore, the acid is deactivated in appearance, and thus, it is possible to carry out the control of acid diffusion.

As the onium salt which becomes a relatively weak acid with respect to the acid generator, compounds represented by the following General Formulae (d1-1) to (d1-3) are preferable.

In the formulae, R⁵¹ is a hydrocarbon group which may have a substituent, Z^(2c) is a hydrocarbon group (provided that carbon adjacent to S is not substituted with a fluorine atom) having 1 to 30 carbon atoms, which may have a substituent, R⁵² is an organic group, Y³ is a linear, branched, or cyclic alkylene group or arylene group, Rf is a hydrocarbon group containing a fluorine atom, and M⁺'s are each independently a sulfonium or iodonium cation.

Preferred examples of the sulfonium cation or the iodonium cation represented by M⁺ include sulfonium cations and iodonium cations represented by the general formulae (ZI) and (ZII), respectively.

Preferred examples of the anionic moiety of the compound represented by General Formula (d1-1) include the structures exemplified in paragraph “0198” of JP2012-242799A.

Preferred examples of the anionic moiety of the compound represented by General Formula (d1-2) include the structures exemplified in paragraph “0201” of JP2012-242799A.

Preferred examples of the anionic moiety of the compound represented by General Formula (d1-3) include the structures exemplified in paragraph “0209” and “0210” of JP2012-242799A.

The onium salt which becomes a relatively weak acid with respect to the acid generator may be a compound (C) (hereinafter also referred to as a “compound (CA)”) which has a cationic moiety and an anionic moiety in the same molecule, and further, the cationic moiety and the anionic moiety are linked to each other via a covalent bond.

As the compound (CA), a compound represented by any one of the following General Formulae (C-1) to (C-3) is preferable.

In General Formulae (C-1) to (C-3),

R₁, R₂, and R₃ represent a substituent having 1 or more carbon atoms,

L₁ represents a divalent linking group that links a cationic moiety with an anionic moiety, or a single bond,

—X⁻ represents an anionic moiety selected from —OCO⁻, —SO₃ ⁻, —SO₂ ⁻, and —N⁻R₄. R₄ represents a monovalent substituent having a carbonyl group: —C(═O)—, a sulfonyl group: —S(═O)₂—, or a sulfinyl group: —S(═O)— at a site for linking to an adjacent N atom, and

R₁, R₂, R₃, R₄, and L₁ may be bonded to one another to form a ring structure. Further, in (C-3), two of R₁ to R₃ may be combined to form a double bond with an N atom.

Examples of the substituent having 1 or more carbon atoms in R₁ to R₃ include an alkyl group, a cycloalkyl group, an aryl group, an alkyloxycarbonyl group, a cycloalkyloxycarbonyl group, an aryloxycarbonyl group, an alkylaminocarbonyl group, a cycloalkylaminocarbonyl group, and an arylaminocarbonyl group, and preferably an alkyl group, a cycloalkyl group, and an aryl group.

Examples of L₁ as a divalent linking group include a linear or branched alkylene group, a cycloalkylene group, an arylene group, a carbonyl group, an ether bond, ester bond, amide bond, a urethane bond, a urea bond, and a group formed by a combination of two or more kinds of these groups. L₁ is more preferably alkylene group, an arylene group, an ether bond, ester bond, and a group formed by a combination of two or more kinds of these groups.

Preferred examples of the compound represented by General Formula (C-1) include the compounds exemplified in paragraphs “0037” to “0039” of JP2013-6827A and paragraphs “0027” to “0029” of JP2013-8020.

Preferred examples of the compound represented by General Formula (C-2) include the compounds exemplified in paragraphs “0012” to “0013” of JP2012-189977A.

Preferred examples of the compound represented by General Formula (C-3) include the compounds exemplified in paragraphs “0029” to “0031” of JP2012-252124A.

The content of the onium salt which becomes a relatively weak acid with respect to the acid generator is preferably 0.5% by mass to 10.0% by mass, more preferably 0.5% by mass to 8.0% by mass, and still more preferably 1.0% by mass to 8.0% by mass, with respect to the solid content of the composition.

[5] Solvent

The composition usually contains a solvent.

Examples of the solvent which can be used in the preparation of the composition include organic solvents such as alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, alkyl alkoxypropionate, a cyclic lactone (preferably having 4 to 10 carbon atoms), a monoketone compound (preferably having 4 to 10 carbon atoms) which may have a ring, alkylene carbonate, alkyl alkoxyacetate, and alkyl pyruvate.

Specific examples of these solvents include those described in “0441” to “0455” of US2008/0187860A.

In the present invention, a mixed solvent obtained by mixing a solvent containing a hydroxyl group and a solvent containing no hydroxyl group in the structure may be used as the organic solvent.

As the solvent containing a hydroxyl group and the solvent containing no hydroxyl group, the aforementioned exemplary compounds can be appropriately selected and used, but as the solvent containing a hydroxyl group, an alkylene glycol monoalkyl ether, alkyl lactate, and the like are preferable, and propylene glycol monomethyl ether (PGME, alternative name: 1-methoxy-2-propanol) and ethyl lactate are more preferable. Further, as the solvent containing no hydroxyl group, an alkylene glycol monoalkyl ether acetate, alkyl alkoxy propionate, a monoketone compound which may contain a ring, cyclic lactone, alkyl acetate, and the like are preferable. Among these, propylene glycol monomethyl ether acetate (PGMEA, alternative name: 1-methoxy-2-acetoxypropane), an ethyl ethoxypropionate, 2-heptanone, y-butyrolactone, cyclohexanone, and butyl acetate are particularly preferable, and propylene glycol monomethyl ether acetate, an ethyl ethoxypropionate, and 2-heptanone are most preferable.

The mixing ratio (based on the mass) of the solvent containing a hydroxyl group and the solvent containing no hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, and more preferably 20/80 to 60/40. A mixed solvent whose proportion of the solvent containing no hydroxyl group is 50% by mass or more is particularly preferable from the viewpoint of coating evenness.

The solvent preferably includes propylene glycol monomethyl ether acetate, and is preferably a solvent composed of propylene glycol monomethyl ether acetate alone or a mixed solvent of two or more kinds of solvents containing propylene glycol monomethyl ether acetate.

[6] Surfactant

The composition may or may not further contain a surfactant, but in the case where the composition contains a surfactant, it is more preferable to contain any one of fluorine- and/or silicon-based surfactants (a fluorine-based surfactant, a silicon-based surfactant, and a surfactant having both a fluorine atom and a silicon atom), or two or more kinds thereof

By incorporating the surfactant into the composition, it becomes possible to provide a resist pattern which is improved in adhesion and decreased in development defects with good sensitivity and resolution when an exposure light source of 250 nm or less, and particularly 220 nm or less, is used.

Examples of the fluorine- and/or silicon-based surfactants include the surfactants described in “0276” of US2008/0248425A.

In addition, in the present invention, a surfactant other than the fluorine- and/or silicon-based surfactants described in “0280” of US2008/0248425A can also be used.

These surfactants may be used alone or in combination of some kinds thereof.

In the case where the composition contains the surfactant, the amount of the surfactant used is preferably 0.0001% by mass to 2% by mass, and more preferably 0.0005% by mass to 1% by mass, with respect to the total solid content of the composition.

On the other hand, by setting the amount of the surfactant added to 10 ppm or less with respect to the total amount (excluding the solvent) of the composition, the hydrophobic resin is more unevenly distributed to the surface, so that the resist film surface can be made more hydrophobic, which can enhance the water tracking properties during the liquid immersion exposure.

[7] Other Additives

The composition of the present invention may or may not contain an onium carboxylate salt. Examples of such an onium carboxylate salt include those described in “0605” to “0606” of US2008/0187860A.

The onium carboxylate salt can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide, and carboxylic acid with silver oxide in a suitable solvent.

In the case where the composition contains the onium carboxylate salt, the content of the salt is generally 0.1% by mass to 20% by mass, preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 7% by mass, with respect to the total solids of the composition.

The composition of the present invention may further contain an acid amplifier, a dye, a plasticizer, a light sensitizer, a light absorbent, an alkali-soluble resin, a dissolution inhibitor, a compound promoting solubility in a developer (for example, a phenol compound with a molecular weight of 1,000 or less, and an alicyclic or an aliphatic compound having a carboxyl group), and the like, if desired.

Such a phenol compound having a molecular weight of 1,000 or less may be easily synthesized by those skilled in the art with reference to the method disclosed in, for example, JP1992-122938A (JP-H04-122938A), JP1990-28531A (JP-H02-28531A), US4916210A, EP219294B, and the like.

Specific examples of the alicyclic or aliphatic compound having a carboxyl group include, but not limited to, a carboxylic acid derivative having a steroid structure such as cholic acid, deoxycholic acid, and lithocholic acid, an adamantane carboxylic acid derivative, adamantane dicarboxylic acid, cyclohexane carboxylic acid, and cyclohexane dicarboxylic acid.

The composition in the present invention is preferably a resist film having a film thickness of 80 nm or less from the viewpoint of improving the resolving power. It is possible to set the film thickness by setting the solid content concentration in the composition to an appropriate range to have suitable viscosity to improve coatability and film formability.

The solid content concentration of the composition in the present invention is usually 1.0% by mass to 10% by mass, preferably 2.0% by mass to 5.7% by mass, and more preferably 2.0% by mass to 5.3% by mass. By setting the solid content concentration to these ranges, it is possible to uniformly apply the resist solution on a substrate, and additionally, it is possible to form a resist pattern with excellent line-width-roughness. The reason is not clear; however, it is considered that, by setting the solid content concentration to 10% by mass or less, and preferably 5.7% by mass or less, the aggregation of materials, particularly the photoacid generator, in the resist solution is suppressed and, as the result, it is possible to form a uniform resist film.

The solid content concentration is a weight percentage of the weight of other resist components excluding the solvent with respect to the total weight of the composition.

The composition in the present invention is used by dissolving the components in a predetermined organic solvent, and preferably in the mixed solvent, filtering the solution through a filter, and then applying the filtered solution on a predetermined support (substrate). The filter used for filtration is preferably a polytetrafluoroethylene-, polyethylene- or nylon-made filter having a pore size of 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.03 μm or less. In the filtration through a filter, as described in, for example, JP2002-62667A, circulating filtration may be carried out, or the filtration may be carried out by connecting two or more kinds of filters in series or in parallel. In addition, the composition may be filtered a plurality of times. Furthermore, the composition may be subjected to a deaeration treatment or the like before or after filtration through a filter.

The composition of the present invention is related to an actinic ray-sensitive or radiation-sensitive resin composition whose properties change by a reaction upon irradiation with actinic ray or radiation. More specifically, the present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition which can be used in for a process for manufacturing a semiconductor such as an IC, for the manufacture of liquid crystals and a circuit board for a thermal head or the like, the manufacture of a mold structure for imprinting, or other photofabrication processes, or used in a lithographic printing plate or an acid-curable composition.

[8] Pattern Forming Method

Next, the pattern forming method according to the present invention will be described.

The pattern forming method of the present invention has at least the following steps:

(a) a step of forming a film including the composition of the present invention (an actinic ray-sensitive or radiation-sensitive resin composition film, a composition film, or a resist film) on a substrate,

(b) a step of irradiating (exposing) the film with actinic ray or radiation (exposing step), and

(c) a step of developing the film irradiated with actinic ray or radiation using a developer (developing step).

The exposure in the step (b) may be a liquid immersion exposure.

The pattern forming method of the present invention preferably includes a (d) heating step after the (b) exposing step.

The pattern forming method of the present invention may include the (b) exposing step in plural times.

The pattern forming method of the present invention may include the (d) heating step in plural times.

The resist film of the present invention is formed of the composition of the present invention, and more specifically, is preferably a film which is formed by applying the composition on a substrate. In the pattern forming method of the present invention, it is possible to carry out a step of forming a film on a substrate using the composition, a step of exposing the film, and a developing step by a general known method.

The substrate on which the film is formed in the present invention is not particularly limited, and it is possible to use an inorganic substrate such as silicon, SiO₂, and SiN, a coating type inorganic substrate such as SOG, or a substrate generally used in a process for manufacturing a semiconductor such as an IC, in a process for the manufacture of liquid crystals and a circuit board for a thermal head or the like, and used in other lithographic processes of photofabrication. Further, if desired, an antireflection film may be formed between the resist film and the substrate. As the antireflection film, a known organic or inorganic antireflection film can be appropriately used.

It is also preferable that the method includes a pre-heating step (PB; Prebake) after forming a film and before the exposing step.

In addition, it is also preferable that the method includes a step of heating after exposure (PEB: Post Exposure Bake), after the exposing step and before the development step.

For both PB and PEB, the heating is preferably carried out at a heating temperature of 70° C. to 130° C., and more preferably 80° C. to 120° C.

The heating time is preferably 30 seconds to 300 seconds, more preferably 30 seconds to 180 seconds, and still more preferably 30 seconds to 90 seconds.

The heating may be carried out using a device installed in an ordinary exposure-and-development machine, or may also be carried out using a hot plate or the like.

The baking accelerates the reaction in the exposed areas, and thus, the sensitivity and the pattern profile are enhanced.

The light source wavelength used in the exposure device in the present invention is not particularly limited, and examples thereof include infrared rays, visible light, ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays, X-rays, and electron beams, for example, far ultraviolet rays at a wavelength of preferably 250 nm or less, more preferably 220 nm or less, and particularly preferably 1 nm to 200 nm, specifically a KrF excimer laser (248 nm), an ArF excimer laser (193 nm), an F₂ excimer laser (157 nm), X-rays, EUV (13 nm), electron beams, and the like, with the KrF excimer laser, the ArF excimer laser, EUV, or the electron beams being preferable, and the ArF excimer laser being more preferable.

Furthermore, a liquid immersion exposure method can be applied to the step of carrying out exposure of the present invention. It is possible to combine the liquid immersion exposure method with super-resolution technology such as a phase shift method and a modified illumination method.

In the case of carrying out the liquid immersion exposure, a step of cleaning the surface of a film with an aqueous chemical liquid may be carried out (1) after forming a film on a substrate and before an exposing step, and/or (2) after a step of subjecting the film to exposure through an immersion liquid and before heating the film.

The immersion liquid is preferably a liquid which is transparent to exposure wavelength and has a minimum temperature coefficient of refractive index so as to minimize the distortion of an optical image projected on the film. In particular, in the case where the exposure light source is an ArF excimer laser (wavelength: 193 nm), water is preferably used in terms of easy availability and easy handling, in addition to the above-described viewpoints.

In the case of using water, an additive (liquid) that decreases the surface tension of water while increasing the interfacial activity may be added at a slight proportion. It is preferable that this additive does not dissolve the resist film of a wafer, and gives a negligible effect on the optical coat at the undersurface of a lens element.

Such an additive is preferably for example, an aliphatic alcohol having a refractive index substantially equal to that of water, and specific examples thereof include methyl alcohol, an ethyl alcohol, and isopropyl alcohol. By adding an alcohol having a refractive index substantially equal to that of water, even when the alcohol component in water is evaporated and its content concentration is changed, an advantage in that the change in the refractive index of the liquid as a whole can be advantageously made very small is obtained.

On the other hand, in the case where materials opaque to light at 193 nm or impurities having a great difference in the refractive index from water are incorporated, the distortion of an optical image projected on a resist is caused. Therefore, the water to be used is preferably distilled water. Further, pure water after filtration through an ion exchange filter or the like may also be used.

The electrical resistance of water used as the immersion liquid is preferably 18.3 MΩcm or more, and Total Organic Concentration (TOC) is preferably 20 ppb or less. The water is preferably one which has been subjected to a deaeration treatment.

In addition, the lithography performance can be enhanced by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index, for example, may be added to water, or heavy water (D₂O) may be used in place of water.

The receding contact angle of the resist film formed using the composition in the present invention is preferably 70° or more at a temperature of 23±3° C. at a humidity of 45±5%, which is appropriate in the case of the exposure through a liquid immersion medium. The receding contact angle is preferably 75° or more, and more preferably 75° to 85°.

If the receding contact angle is extremely small, the resist film cannot be appropriately used in the case of the exposure through a liquid immersion medium. Further, it is not possible to sufficiently exhibit the effect of reducing defects due to remaining water (water marks). In order to realize a favorable receding contact angle, it is preferable to incorporate the hydrophobic resin (D) into the composition. Alternatively, a film (hereinafter also referred to as a “top coat”) sparingly soluble in an immersion liquid formed of the hydrophobic resin (D) may be provided on the upper layer of the resist film. The functions required for the top coat are coating suitability with respect to the upper layer part on a resist film and sparingly soluble properties in an immersion liquid. The top coat which is not mixed with a composition film and can be uniformly applied on the upper layer of the composition film is preferable.

Specific examples of the top coat include a hydrocarbon polymer, an acrylic acid ester polymer, a polymethacrylic acid, a polyacrylic acid, a polyvinyl ether, a silicon-containing polymer, and a fluorine-containing polymer. From the viewpoint that the optical lens is contaminated when impurities are eluted from the top coat to the immersion liquid, it is preferable that the amounts of residual monomer components of the polymer included in the top coat are small.

When the top coat is peeled off, a developer may be used or a separate peeling agent may be used. As the peeling agent, a solvent having low penetration into the film is preferable. From the viewpoint that the peeling step can be carried out at the same time with the developing step the film, it is preferable that the top coat can be peeled off by the developer containing an organic solvent.

When there is no difference in the refractive index between the top coat and the immersion liquid, the resolving power is improved. In the case where water is used as the immersion liquid, it is preferable that the top coat has a refractive index close to the refractive index of the immersion liquid. From the viewpoint of setting the refractive index close to that of the immersion liquid, it is preferable that the top coat has a fluorine atom. Further, from the viewpoint of the transparency and the refractive index, the top coat is preferably a thin film.

It is preferable that the top coat is not mixed with the film nor with the immersion liquid. From this viewpoint, in the case where the immersion liquid is water, it is preferable that the solvent used for the top coat is sparingly soluble in the solvent used for the composition of the present invention and is a water-insoluble medium. In addition, in the case where the immersion liquid is an organic solvent, the top coat may be water-soluble or water-insoluble.

In the case of the liquid immersion exposure, formation of the top coat layer is not limited, and may also be carried out in the case of dry exposure (exposure not through an immersion liquid). By forming the top coat layer, for example, generation of outgases can be inhibited.

Hereinafter, the top coat composition used for formation of the top coat layer will be described.

For the top coat composition in the present invention, the solvent is preferably an organic solvent, and more preferably an alcohol-based solvent.

In the case where the solvent is an organic solvent, the solvent which does not dissolve the resist film is preferable. As the usable solvent, an alcohol-based solvent, a fluorine-based solvent, or a hydrocarbon-based solvent is preferably used, and a non-fluorine-based and alcohol-based solvent is more preferably used. Among the alcohol-based solvents, from the viewpoint of coatability, a primary alcohol is preferable, and a primary alcohol having 4 to 8 carbon atoms is more preferable. As the primary alcohol having 4 to 8 carbon atoms, a linear, branched, or cyclic alcohol can be used, and preferred examples thereof include 1-butanol, 1-hexanol, 1-pentanol, 3-methyl-1-butanol, 2-ethylbutanol, and perfluorobutyl tetrahydrofuran.

Furthermore, as the resin for a top coat composition, the resins containing acid groups described in JP2009-134177A and JP2009-91798A can also be preferably used.

The weight-average molecular weight of the water-soluble resin is not particularly limited, and is preferably 2,000 to 1,000,000, more preferably 5,000 to 500,000, and particularly preferably 10,000 to 100,000. Herein, the weight-average molecular weight of the resin refers to a polystyrene-equivalent molecular weight measured by GPC (carrier: THF or N-methyl-2-pyrrolidone (NMP)).

The pH of the top coat composition is not particularly limited, but is preferably 0 to 10, more preferably 0 to 8, and particularly preferably 1 to 7.

The concentration of the resin in the top coat composition is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 5% by mass, and particularly preferably 0.3% by mass to 3% by mass.

The top coat material may include components other than the resin, but the proportion of the resin occupying the solid content of the top coat composition is preferably 80% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and particularly preferably 95% by mass to 100% by mass.

The solid content concentration in the top coat composition in the present invention is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 6% by mass, and still more preferably 0.3% by mass to 5% by mass. By setting the solid content concentration to the range, the top coat composition can be uniformly coated on the resist film.

In the pattern forming method of the present invention, a resist pattern can be formed on a substrate using the composition, and a top coat layer can also be formed on the resist film using the top coat composition. The film thickness of the resist film is preferably 10 nm to 100 nm, and the film thickness of the top coat layer is preferably 10 nm to 200 nm, more preferably 20 nm to 100 nm, and particularly preferably 40 nm to 80 nm.

The method for coating the composition on a substrate is preferably spin coating, and the rotation speed is preferably 1,000 rpm to 3,000 rpm.

For example, the composition is coated on a substrate (e.g.: silicon/silicon dioxide coating), such as one for use in the manufacture of precision integrated circuit elements, by appropriate coating means, such as a spinner and a coater, and dried, thereby forming a resist film. Further, a heretofore known antireflection film can also be coated in advance. In addition, it is preferable that the resist film is dried before the top coat layer is formed.

Then, the top coat composition can be coated and dried on the obtained resist film in the same manner as in the method for forming the resist film, thereby forming a top coat layer.

The resist film having the top coat layer provided on the upper layer thereof is exposed, usually through a mask, to actinic ray or radiation, preferably baked (heated), and developed. Thus, a good pattern can be obtained.

In the liquid immersion exposing step, the immersion liquid needs to move on a wafer following the movement of an exposure head that scans on the wafer at a high speed and forms an exposure pattern, and thus the contact angle of the immersion liquid for the resist film in a dynamic state is important, and the resist requires a performance of following the high-speed scanning of the exposure head, while a liquid droplet no longer remains.

A developer for use in the step of developing the actinic ray-sensitive or radiation-sensitive composition film formed using the composition of the present invention is not particularly limited, but, for example, an alkali developer or a developer containing an organic solvent (hereinafter also referred to as an organic developer) can also be used.

As the alkali developer, an alkaline aqueous solution containing, for example, an inorganic alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; a primary amine such as ethylamine and n-propylamine, a secondary amine such as diethylamine and di-n-butylamine, a tertiary amine such as triethylamine and methyldiethylamine; an alcoholamine such as dimethylethanolamine and triethanolamine; a tetraalkylammonium hydroxide such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, ethyltrimethylammonium hydroxide, butyltrimethylammonium hydroxide, methyltriamylammonium hydroxide, and dibutyldipentylammonium hydroxide; a quaternary ammonium salt such as trimethylphenylammonium hydroxide, trimethylbenzylammonium hydroxide, and triethylbenzylammonium hydroxide; or a cycloamine such as pyrrole and piperidine can be used. Further, an appropriate amount of alcohols or a surfactant can be added to the alkaline aqueous solution and the mixture can be used. The alkali concentration of the alkali developer is usually 0.1% by mass to 20% by mass. The pH of the alkali developer is usually 10.0 to 15.0. The alkali concentration and the pH of the alkali developer can be appropriately adjusted and used. A surfactant or an organic solvent is added to the alkali developer and the mixture is used.

As the rinsing liquid in the rinse treatment carried out after the alkali development, pure water is used, and further, an appropriate amount of a surfactant can also be added thereto and used.

In addition, after the development treatment or the rinse treatment, a treatment of removing the developer or rinsing liquid adhering on the pattern by a supercritical fluid can be carried out.

As the organic developer, a polar solvent such as a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, an amide-based solvent, and an ether-based solvent, or a hydrocarbon-based solvent can be used.

Examples of the ketone-based solvent include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone (methyl amyl ketone), 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetyl acetone, acetonyl acetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, isophorone, and propylene carbonate.

Examples of the ester-based solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, and propyl lactate.

Examples of the alcohol-based solvent include an alcohol such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, and n-decanol; a glycol-based solvent such as ethylene glycol, diethylene glycol, and triethylene glycol; and a glycol ether-based solvent such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and methoxymethyl butanol.

Examples of the ether-based solvent include, in addition to the glycol ether-based solvents, dioxane and tetrahydrofuran.

As the amide-based solvent, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidinone, and the like can be used.

Examples of the hydrocarbon-based solvent include aromatic hydrocarbon-based solvents such as toluene and xylene, and aliphatic hydrocarbon-based solvents such as pentane, hexane, octane, and decane.

A plurality of these solvents may be mixed, or the solvent may be used by mixing it with a solvent other than those described above or with water. However, in order to sufficiently bring out the effects of the present invention, the water content ratio in the entire developer is preferably less than 10% by mass, and it is more preferable that the developer contains substantially no water.

That is, the amount of the organic solvent to be used in the organic developer is preferably 90% by mass to 100% by mass, and more preferably 95% by mass to 100% by mass, with respect to the entire amount of the developer.

Particularly, the organic developer is preferably a developer containing at least one kind of organic solvent selected from the group consisting of a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, an amide-based solvent, and an ether-based solvent.

The vapor pressure of the organic developer is preferably 5 kPa or less, more preferably 3 kPa or less, and particularly preferably 2 kPa or less, at 20° C. By setting the vapor pressure of the organic developer to 5 kPa or less, the evaporation of the developer on a substrate or in a development cup is inhibited, and the temperature uniformity within a wafer plane is improved, whereby the dimensional uniformity within a wafer plane is enhanced.

An appropriate amount of a surfactant may be added to the organic developer, if desired.

The surfactant is not particularly limited, and for example, an ionic or nonionic, fluorine- and/or silicon-based surfactant can be used. Examples of such a fluorine- and/or silicon-based surfactant include surfactants described in JP1987-36663A (JP-S62-36663A), JP1986-226746A (JP-S61-226746A), JP1986-226745A (JP-S61-226745A), JP1987-170950A (JP-S62-170950A), JP1988-34540A (JP-S63-34540A), JP1995-230165A (JP-H07-230165A), JP1996-62834A (JP-H08-62834A), JP1997-54432A (JP-H09-54432A), JP1997-5988A (JP-H09-5988A), and U.S. Pat. No. 5,405,720A, U.S. Pat. No. 5,360,692A, U.S. Pat. No. 5,529,881A, U.S. Pat. No. 5,296,330A, U.S. Pat. No. 5,436,098A, U.S. Pat. No. 5,576,143A, U.S. Pat. No. 5,294,511A, and U.S. Pat. No. 5,824,451A, with the nonionic surfactant being preferable. The nonionic surfactant is not particularly limited, but the fluorine-based surfactant or the silicon-based surfactant is more preferably used.

The amount of the surfactant used is usually 0.001% by mass to 5% by mass, preferably 0.005% by mass to 2% by mass, and more preferably 0.01% by mass to 0.5% by mass, with respect to the total amount of the developer.

The organic developer may also include a basic compound. Specific examples of the basic compound which may included in the organic developer used in the present invention, and preferred examples thereof are the same as those for the basic compounds which can be included in the composition described above as an acid diffusion inhibitor.

As the developing method, for example, a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (a dip method), a method in which a developer is heaped up to the surface of a substrate by surface tension and developed by resting for a certain period of time (a paddle method), a method in which a developer is sprayed on the surface of a substrate (a spray method), a method in which a developer is continuously discharged on a substrate spun at a constant rate while scanning a developer discharging nozzle at a constant rate (a dynamic dispense method), or the like, can be applied.

In the case where the various developing methods include a process of discharging a developer toward a resist film from a development nozzle of a developing device, the discharge pressure of the developer discharged (the flow velocity per unit area of the developer discharged) is preferably 2 mL/sec/mm² or less, more preferably 1.5 mL/sec/mm² or less, and still more preferably 1 mL/sec/mm² or less. The flow velocity has no particular lower limit, but is preferably 0.2 mL/sec/mm² or more in consideration of throughput.

By setting the discharge pressure of the discharged developer to the aforementioned range, pattern defects resulting from the resist scum after development may be significantly reduced.

Although details on the mechanism are not clear, it is thought to be due to a fact that the pressure imposed on the resist film by the developer is decreased by setting the discharge pressure to the above range so that the resist film and the resist pattern are inhibited from being inadvertently cut or collapsing.

Furthermore, the discharge pressure (mL/sec/mm²) of the developer is a value at the outlet of the development nozzle in the developing device.

Examples of the method for adjusting the discharge pressure of the developer include a method of adjusting the discharge pressure by a pump or the like, and a method of supplying a developer from a pressurized tank and adjusting the pressure to change the discharge pressure.

In addition, after the step of carrying out development using a developer including an organic solvent, a step of stopping the development while replacing the solvent with another solvent may also be carried out.

In the pattern forming method of the present invention, a step of developing with a developer including an organic solvent (organic solvent developing step) and a step of developing with an alkaline aqueous solution (alkali developing step) is used. Thus, a finer pattern can be formed.

In the present invention, areas with low exposure intensity are removed by the organic solvent developing step, while areas with high exposure intensity are removed by the alkali developing step. Thus, this multi-development process in which development is carried out two or more times can realize pattern formation while not dissolving only areas with intermediate exposure intensity, and therefore, finer patterns than usually can be formed (in the same mechanism as described in “0077” of JP2008-292975A).

In the pattern forming method of the present invention, the order of the alkali developing step and organic solvent developing step is not particularly limited, but it is more preferable that the alkali development is carried out before the organic solvent developing step.

It is preferable that a cleaning step using a rinsing liquid is included after the step of performing development using a developer including an organic solvent.

The rinsing liquid used in the rinsing step after the step of carrying out development using a developer including an organic solvent is not particularly limited as long as the rinsing liquid does not dissolve the resist pattern, and a solution including a general organic solvent can be used. As the rinsing liquid, a rinsing liquid containing at least one organic solvent selected from the group consisting of a hydrocarbon-based solvent, a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, an amide-based solvent, and an ether-based solvent is preferably used.

Specific examples of the hydrocarbon-based solvent, the ketone-based solvent, the ester-based solvent, the alcohol-based solvent, the amide-based solvent, and the ether-based solvent are the same as those described above with regard to the developer including an organic solvent.

After the step of carrying out development using a developer containing an organic solvent, a cleaning step using a rinsing liquid containing at least one organic solvent selected from the group consisting of a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, and an amide-based solvent is more preferably carried out, a cleaning step using a rinsing liquid containing an alcohol-based solvent or an ester-based solvent is still more preferably carried out, a cleaning step using a rinsing liquid containing a monohydric alcohol is particularly preferably carried out, and a cleaning step using a rinsing liquid containing a monohydric alcohol having 5 or more carbon atoms is most preferably carried out.

Here, examples of the monohydric alcohol used in the rinsing step include a linear, branched, or cyclic monohydric alcohol, and specifically, 1-butanol, 2-butanol, 3-methyl-1-butanol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 1-hexanol, 4-methyl-2-pentanol, 1-heptanol, 1-octanol, 2-hexanol, cyclopentanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, or the like can be used, and as a particularly preferred monohydric alcohol having 5 or more carbon atoms, 1-hexanol, 2-hexanol, 4-methyl-2-pentanol, 1-pentanol, 3-methyl-1-butanol, or the like can be used.

The respective components in plural numbers may be mixed or the components with another organic solvent may be mixed and used.

The water content of the rinsing liquid is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. By setting the water content to 10% by mass or less, good development characteristics can be obtained.

The vapor pressure of the rinsing liquid which is used after the step of carrying out development using a developer including an organic solvent is preferably 0.05 kPa to 5 kPa, more preferably 0.1 kPa to 5 kPa, and most preferably 0.12 kPa to 3 kPa, at 20° C. By setting the vapor pressure of the rinsing liquid to a range of 0.05 kPa to 5 kPa, the temperature uniformity within a wafer plane is improved, and further, the dimensional uniformity within a wafer plane is enhanced by inhibition of swelling due to the penetration of the rinsing liquid.

The rinsing liquid can also be used after adding an appropriate amount of a surfactant thereto.

In the rinsing step, the wafer which has been subjected to development using a developer including an organic solvent is subjected to a cleaning treatment using the rinsing liquid including an organic solvent. A method for the cleaning treatment is not particularly limited, and for example, a method in which a rinsing liquid is continuously discharged on a substrate rotated at a constant rate (a rotation application method), a method in which a substrate is immersed in a bath filled with a rinsing liquid for a certain period of time (a dip method), a method in which a rinsing liquid is sprayed on a substrate surface (a spray method), or the like, can be applied. Among these, a method in which a cleaning treatment is carried out using the rotation application method, and a substrate is rotated at a rotational speed of 2,000 rpm to 4,000 rpm after cleaning, thereby removing the rinsing liquid from the substrate, is preferable. Further, it is preferable that a heating step (Post Bake) is included after the rinsing step. The residual developer and the rinsing liquid between and inside the patterns are removed by the baking. The heating step after the rinsing step is carried out at typically 40° C. to 160° C., and preferably at 70° C. to 95° C., and typically for 10 seconds to 3 minutes, and preferably for 30 seconds to 90 seconds.

Furthermore, the present invention further relates to a method for manufacturing an electronic device, including the pattern formation method of the present invention as described above, and an electronic device manufactured by the manufacturing method.

The electronic device of the present invention is suitably mounted on electric or electronic equipment (home electronics, OA/media-related equipment, optical equipment, telecommunication equipment, and the like).

EXAMPLES

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto.

Various components used in Table 3 below are summarized below.

Synthesis Example 1

[Synthesis of Monomer]

4-Ethylcyclohexanone (126.2 g) was added to tetrahydrofuran (200 mL), and the mixture was cooled to 0° C. Then, 110 mL of cyclopentylmagnesium bromide (1 mol/L tetrahydrofuran solution) was added dropwise thereto at 0° C. The reaction mixture was warmed to room temperature, stirred for 1 hour, and then cooled to 0° C., and 50 mL of water was added thereto. The product was extracted five times from the aqueous phase with 100 mL of ethyl acetate. The organic phase was combined and washed with water, and then the solvent was distilled off. The crude product thus obtained was purified by silica gel chromatography to obtain 177 g of a compound A (yield of 90%).

The compound A (196 g) was added to 300 mL of tetrahydrofuran and cooled to −40° C.

69 mL of normal butyllithium (1.6 mol/L hexane solution) was added dropwise thereto at −40° C., and the mixture was stirred at 0° C. for 1 hour. The reaction liquid was cooled to −40° C. again and then 106 mL of methacryloyl chloride was added dropwise thereto. The reaction mixture was warmed to room temperature, stirred for 1 hour, and then cooled to 0° C., and 100 mL of water was added thereto. The product was extracted five times from the aqueous phase with 100 mL of ethyl acetate. The organic phase was combined and washed with water, and then the solvent was distilled off. The crude product thus obtained was purified by silica gel chromatography to obtain a monomer (212 g) (yield of 85%).

[Synthesis of Polymer]

Cyclohexanone (94.18 parts by mass) was heated to 80° C. under a nitrogen gas flow. While stirring this liquid, a mixed solution of a monomer represented by Structural Formula M-1 (20.45 parts by mass), a monomer represented by Structural Formula M-2 (20.96 parts by mass), a monomer represented by Structural Formula M-3 (6.08 parts by mass), cyclohexanone (174.91 parts by mass), and dimethyl 2,2′-azobisisobutyrate [V-601, manufactured by Wako Pure Chemical Industries, Ltd.] (1.74 parts by mass) was added dropwise thereto for 6 hours. After completion of the dropwise addition, the mixture was further stirred at 80° C. for 2 hours. After leaving the reaction liquid to cool, the mixture was reprecipitated with a large amount of methanol/water (mass ratio of 90:10) and filtered, and the obtained solid was vacuum-dried to obtain Polymer 1 (33.6 parts by mass).

In the same manner as in Synthesis Example 1 except that the monomers corresponding to the respective repeating units were used to have desired compositional ratios (molar ratios), Polymers 2 to 14 were synthesized.

Moreover, the numeral values described on the right-handed side of the respective repeating units in the respective Polymers 1 to 14 below represent % by mole of the respective repeating units.

Furthermore, as the resin used in Comparative Examples, the following resins were used.

As the acid generator, the following compounds were used.

As the basic compound, the following compounds were used.

As the hydrophobic resin, the following resins were used.

As the surfactant, the following ones were used.

W-1: Megaface F176 (manufactured by DIC Corp.; fluorine-based)

W-2: PolyFox PF-6320 (manufactured by OMNOVA Solutions Inc.; fluorine-based)

As the solvent, the following ones were used.

SL-1: Propylene glycol monomethyl ether acetate (PGMEA)

SL-2: Butyl lactate

SL-3: Propylene glycol monomethyl ether (PGME)

SL-4: Cyclohexanone

SL-5: y-Butyrolactone

<Preparation of Composition (Resist Composition)>

The components shown in Table 3 below were dissolved in the solvents shown in the same tables such that the solid content became 3.5% by mass, and each of the solutions was filtered through a polyethylene filter having a pore size of 0.03 μm to prepare an actinic ray-sensitive or radiation-sensitive resin composition (resist composition).

TABLE 3 Compositional ratio of resist Acid Basic generator Resin compound Hydrophobic Solvent (mass Surfactant (g) (10 g) (g) resin (0.05 g) ratio) (0.03 g) Example 1 PAG-1 Polymer 1 N-1 (0.1) 1b SL-1/SL-4 W-1 (2.0) (80/20) Example 2 PAG-6 Polymer 2 N-7 (0.12) 1b SL-1/SL-2/SL-3 None (2.0) (90/5/5) Example 3 PAG-4 Polymer 3 N-6 (0.08) 2b SL-1/SL-4/SL-5 None (1.5) (90/5/5) Example 4 PAG-7 Polymer 4 N-5 (0.14) 4b SL-1/SL-4 W-2 (2.0) (80/20) Example 5 PAG-2 Polymer 5 N-2 (0.08) 3b SL-1/SL-3 None (2.0) N-8 (0.05) (90/10) Example 6 PAG-3 Polymer 6 N-2 (0.06) 2b SL-1/SL-3 None (2.0) N-9 (0.07) (70/30) Example 7 PAG-8 Polymer 7 N-9 (0.12) 2b SL-1/SL-4 W-2 (2.0) (65/35) Example 8 PAG-5 Polymer 8 N-3 (0.1) 4b SL-1/SL-4 None (2.0) (70/30) Example 9 PAG-1 Polymer 9 N-4 (0.1) 1b SL-1/SL-3 None (1.5) (65/35) Example 10 PAG-4 Polymer N-4 (0.1) 1b SL-1/SL-3 None (1.5) 10 (65/35) Example 11 PAG-4 Polymer N-4 (0.1) 1b SL-1/SL-3 None (1.5) 11 (65/35) Example 12 PAG-1 Polymer N-4 (0.1) 1b SL-1/SL-3 None (1.5) 12 (65/35) Example 13 PAG-4 Polymer 9 N-4 (0.1) 1b (0.03 g) SL-1/SL-3 None (2.0) 2b (0.02 g) (65/35) Example 14 PAG-7 Polymer 9 N-4 (0.1) 1b (0.03 g) SL-1/SL-3 None (2.0) 2b (0.02 g) (65/35) Example 15 PAG-1 Polymer N-7 (0.12) 1b SL-1/SL-3 None (1.0) 1 (5 g) (65/35) PAG-4 Polymer (0.5) 9 (5 g) Example 16 PAG-1 Polymer N-9 (0.14) 1b SL-1/SL-3 None (1.0) 1 (5 g) (65/35) PAG-4 Polymer (0.5) 9 (5 g) Comparative PAG-1 Polymer N-4 (0.1) 1b SL-1/SL-3 None Example 1 (2.0) 13 (65/35) Comparative PAG-1 Polymer N-4 (0.1) 1b SL-1/SL-3 None Example 2 (2.0) 14 (65/35)

<Pattern Forming Method (Negative Tone, Organic Solvent Development)>

Si-BARC (manufactured by BSI) for forming an antireflection film was applied onto a silicon wafer (12-inch aperture) and baked at 205° C. for 60 seconds to form an antireflection film having a film thickness of 30 nm. The prepared compositions of Examples and Comparative Examples were applied thereonto and baked at 90° C. for 60 seconds to form a photosensitive film (resist film) having a film thickness of 85 nm, thereby obtaining a wafer. The obtained wafer was exposed using an ArF excimer laser liquid immersion scanner (manufactured by ASML, XT1700i, NA 1.20, C-Quad, outer sigma 0.750, inner sigma 0.650, XY deflection) through a 6% halftone mask having a 1:1 line-and-space pattern with a line width of 50 nm. Ultrapure water was used as the immersion liquid. After the film was heated at 100° C. for 60 seconds, the film was developed by paddling with butyl acetate for 30 seconds, rinsed by paddling with 4-methyl-2-pentanol for 30 seconds while spinning the wafer at a rotational speed of 1,000 rpm, and then spin-dried to obtain a resist pattern having 1:1 line-and-space with a line width of 50 nm.

<Method for Evaluating Depth of Focus (DOF: Depth of Focus)>

In the exposure dose for forming a line pattern with a line width of 50 nm under the exposure/development conditions of <Pattern Forming Method> above, exposure and development were carried out by changing the condition of the exposure focus by a 10 nm unit in the focus direction. The space line width (CD) of each of the obtained patterns was measured using a line width length-measuring scanning electron microscope SEM (S-9380, manufactured by Hitachi, Ltd.), and a focus corresponding to the minimum value or the maximum value of a curve obtained by plotting the respective CDs was defined as a best focus. When the focus was changed around the best focus at a center, the variation width of the focus allowing the line width to be 50 nm±10%, that is, a depth (nm) of focus was calculated. A higher value of the depth of focus is more preferable.

The results of the respective Examples and Comparative Examples are shown in Table 4 below.

TABLE 4 DOF (nm) Example 1 114 Example 2 116 Example 3 116 Example 4 117 Example 5 118 Example 6 117 Example 7 116 Example 8 117 Example 9 119 Example 10 118 Example 11 121 Example 12 116 Example 13 120 Example 14 124 Example 15 121 Example 16 119 Comparative Example 1 98 Comparative Example 2 101

As shown in Table 4, it was confirmed that when the composition of the present invention was used, the depth of focus was superior. Among these, from comparison between Examples 9 and 12, it was confirmed that in Example 9 in which two organic groups are bonded to the same carbon atom in the alkylene group in the partial structure represented by General Formula (X), superior effects were obtained.

On the other hand, in Comparative Examples 1 and 2 in which the resin used in JP3800318B was used, desired effects could not be obtained. 

What is claimed is:
 1. An actinic ray-sensitive or radiation-sensitive resin composition comprising: a resin (P) having a partial structure represented by General Formula (X), and a compound capable of generating an acid upon irradiation with actinic ray or radiation,

wherein in General Formula (X), R₁ to R₃ each independently represents a hydrogen atom or an organic group, at least two of R₁ to R₃ are bonded to each other to form a ring structure, Z is a divalent alkylene group having 2 or more carbon atoms, and at least one of hydrogen atoms in the alkylene group is substituted with an organic group; the alkylene group may contain two or more of the organic groups, and a plurality of the organic groups is not bonded to each other to form a ring structure; and * represents a bonding position.
 2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the ring structure formed by the mutual bonding of at least two of R₁ to R₃ is a monocyclic cycloalkyl group.
 3. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the organic group is an alkyl group.
 4. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 2, wherein the organic group is an alkyl groups.
 5. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein at least two of hydrogen atoms in the alkylene group are substituted with the organic group.
 6. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 2, wherein at least two of hydrogen atoms in the alkylene group are substituted with the organic group.
 7. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 3, wherein at least two of hydrogen atoms in the alkylene group are substituted with the organic group.
 8. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 4, wherein at least two of hydrogen atoms in the alkylene group are substituted with the organic group.
 9. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 5, wherein the organic group is bonded to the same carbon atom in the alkylene group.
 10. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 6, wherein the organic group is bonded to the same carbon atom in the alkylene group.
 11. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 7, wherein the organic group is bonded to the same carbon atom in the alkylene group.
 12. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 8, wherein the organic group is bonded to the same carbon atom in the alkylene group.
 13. A pattern forming method comprising at least: (a) forming an actinic ray-sensitive or radiation-sensitive resin composition film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1; (b) irradiating the film with actinic ray or radiation; and (c) developing the film irradiated with actinic ray or radiation using a developer.
 14. The pattern forming method according to claim 13, wherein the developer is a developer including an organic solvent.
 15. A method for manufacturing an electronic device, comprising the pattern forming method according to claim
 13. 